Organization and Summary of Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The preparation of financial statements in conformity with generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and footnotes. Examples include, but are not limited to, estimates of accounts receivable allowances, professional and general liabilities and the estimate of deferred tax assets or liabilities. Actual results could differ from those estimates.
Principles of Consolidation	The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, as well as interests in partnerships and limited liability companies controlled by the Company through its ownership of a majority voting interest or other rights granted to the Company by contract to manage and control the affiliate's business. All significant intercompany balances and transactions are eliminated in consolidation.
Variable Interest Entities	Variable Interest Entities The consolidated financial statements include the accounts of variable interest entities ("VIE") in which the Company is the primary beneficiary under the provisions of Accounting Standards Codification 810, Consolidation. The Company has the power to direct the activities that most significantly impact a variable interest entity's economic performance. Additionally, the Company would absorb the majority of the expected losses from any of these entities should such expected losses occur. At December 31, 2020, the variable interest entities include four surgical facilities and three physician practices.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The fair value of a financial instrument is the amount at which the instrument could be exchanged in an orderly transaction between market participants to sell the asset or transfer the liability. The Company uses fair value measurements based on inputs classified into the following hierarchy: •Level 1: Unadjusted quoted prices in active markets for identical assets or liabilities. •Level 2: Inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly. These may include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. •Level 3: Unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions, depending on the nature of the item being valued. The carrying amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, restricted invested assets and accounts payable approximate their fair values under Level 3 calculations. The fair values in the table above were based on a Level 2 inputs using quoted prices for identical liabilities in inactive markets. The carrying amounts related to the Company's other long-term debt obligations, including finance lease obligations, approximate their fair values under Level 3 calculations.The fair value of these derivative financial instruments was based on a quoted market price, or a Level 2 input.
Revenues	Revenues The Company's revenues generally relate to contracts with patients in which the performance obligations are to provide health care services. The Company recognizes revenues in the period in which our obligations to provide health care services are satisfied and reports the amount that reflects the consideration the Company expects to be entitled to receive. The contractual relationships with patients, in most cases, also involve a third-party payor (e.g., Medicare, Medicaid and private insurance organizations, including plans offered through the health insurance exchanges) and the transaction prices for the services provided are dependent upon the terms provided by or negotiated with the third-party payors. The payment arrangements with third-party payors for the services provided to the related patients typically specify payments at amounts less than the Company's standard charges. The Company continually reviews the contractual estimation process to consider and incorporate updates to laws and regulations and the frequent changes in managed care contractual terms resulting from contract renegotiations and renewals. Patient service revenues. This revenue is related to charging facility fees in exchange for providing patient care. The fee charged for health care procedures performed in surgical facilities varies depending on the type of service provided, but usually includes all charges for usage of an operating room, a recovery room, special equipment, medical supplies, nursing staff and medications. The fee does not normally include professional fees charged by the patient’s surgeon, anesthesiologist or other attending physician, which are billed directly by such physicians to the patient or third-party payor. However, in several surgical facilities, the Company charges for anesthesia services. Ancillary service revenues include fees for patient visits to the Company's physician practices, pharmacy services and diagnostic tests ordered by physicians. Patient service revenues are recognized as performance obligations are satisfied. Performance obligations are based on the nature of services provided. Typically, the Company recognizes revenue at a point in time in which services are rendered and the Company has no obligation to provide further patient services. As the Company primarily performs outpatient procedures, performance obligations are generally satisfied same day and revenue is recognized on the date of service. The Company determines the transaction price based on gross charges for services provided, net of estimated contractual adjustments, discounts from third-party payors. The Company estimates its contractual adjustments and discounts based on contractual agreements, its discount policies and historical experience. Changes in estimated contractual adjustments and discounts are recorded in the period of change. Other service revenues. Optical service revenues consist of handling charges billed to the members of the Company's optical products purchasing organization. The Company's optical products purchasing organization negotiates volume buying discounts with optical products manufacturers. The buying discounts and any handling charges billed to the members of the buying group represent the revenue recognized for financial reporting purposes. The Company satisfies the performance obligation and recognizes revenue when the orders are shipped to members. The Company bases its estimates for sales returns and discounts on historical experience and has not experienced significant fluctuations between estimated and actual return activity and discounts given. The Company sold its optical products purchasing organization on December 31, 2020. Other revenues include management and administrative service fees derived from the non-consolidated facilities that the Company accounts for under the equity method, management of surgical facilities in which it does not own an interest, and management services provided to physician practices for which the Company is not required to provide capital or additional assets. These agreements typically require the Company to provide recurring management services over a multi-year period which are billed and collected on a monthly basis. The fees derived from these management arrangements are based on a predetermined percentage of the revenues of each facility or practice and are recognized in the period in which management services are rendered and billed.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company maintains its cash and cash equivalent balances at high credit quality financial institutions. Cash, cash equivalents and restricted cash reported within the consolidated statement of cash flows includes $0.3 million of restricted investments, which are reflected in other long-term assets in the consolidated balance sheet at both December 31, 2020 and 2019. These restricted investments represent restricted cash held in accordance with the provisions of a long-term operating lease agreement held as security for performance under the Company's covenants and obligations within the agreement through January 2024.
Accounts Receivable	Accounts Receivable Accounts receivable from third-party payors are recorded net of estimated implicit price concessions, which are estimated based on the historical trend of the Company's surgical hospitals’ cash collections and contractual write-offs, and for the Company's surgical facilities in general, established fee schedules, relationships with payors and procedure statistics. While changes in estimated reimbursement from third-party payors remain a possibility, the Company expects that any such changes would be minimal and, therefore, would not have a material effect on its financial condition or results of operations. Accounts receivable consists of receivables from federal and state agencies (under the Medicare and Medicaid programs), private insurance organizations, employers and patients. Management recognizes that revenues and receivables from government agencies are significant to the Company's operations, but it does not believe that there is significant credit risk associated with these government agencies. Concentration of credit risk with respect to other payors is limited because of the large number of such payors. The Company recognizes that final reimbursement of accounts receivable is subject to final approval by each third-party payor. However, because the Company has contracts with its third-party payors and also verifies insurance coverage of the patient before medical services are rendered, the amounts that are pending approval from third-party payors are not considered significant. Amounts are classified outside of self-pay if the Company has an agreement with the third-party payor or has verified a patient’s coverage prior to services rendered. The Company's policy is to collect co-payments and deductibles prior to providing medical services. Patient services of the Company are primarily non-emergency, which allows the surgical facilities to control the procedures for which third-party reimbursement is sought and obtained. The Company does not require collateral from self-pay patients. The Company's collection policies and procedures are based on the type of payor, size of claim and estimated collection percentage for each patient account. The Company analyzes accounts receivable at each of its surgical facilities to ensure the proper collection and aged category. Collection efforts include direct contact with third-party payors or patients, written correspondence and the use of legal or collection agency assistance, as required.
Impairment of Long-Lived Assets, Goodwill and Intangible Assets	Impairment of Long-Lived Assets, Goodwill and Intangible Assets The Company evaluates the carrying value of long-lived assets when impairment indicators are present or when circumstances indicate that impairment may exist. The Company performs an impairment test by preparing an expected undiscounted cash flow projection. If the projection indicates that the recorded amount of the long-lived asset is not expected to be recovered, the carrying value is reduced to estimated fair value. The cash flow projection and fair value represents management’s best estimate, using appropriate and customary assumptions, projections and methodologies, at the date of evaluation. For discussion on impairment for goodwill and indefinite-lived intangible assets, refer to Note 4. "Goodwill and Intangible Assets."
Professional and General and Workers' Compensation Insurance	Professional and General and Workers' Compensation Insurance The Company maintains general liability and professional liability insurance in excess of self-insured retentions through third party commercial insurance carriers in amounts that management believes is sufficient for the Company's operations, although, potentially, some claims may exceed the scope of coverage in effect. The professional liability insurance coverage is on a claims-made basis and the general liability insurance is on an occurrence basis. The Company also maintains workers' compensation insurance, subject to a self-insured retention. The Company expenses the costs under the self-insured retention exposure for general and professional liability and workers' compensation claims which relate to (i) claims made during the policy period, which are offset by insurance recoveries and (ii) an estimate of claims incurred but not yet reported that are expected to be reported after the policy period expires. Reserves and provisions are based upon actuarially determined estimates using individual case-basis valuations and actuarial analysis. Reserves for professional, general and workers' compensation claim liabilities are determined with no regard for expected insurance recoveries and are presented gross on the consolidated balance sheets.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. The Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Derivatives and Hedging ActivitiesThe Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps as part of its interest rate risk management strategy. During 2020 and 2019, such derivatives have been used to hedge the variable cash flows associated with existing variable-rate debt. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive income ("OCI") and subsequently reclassified into interest expense in the same period(s) during which the hedged transaction affects earnings, as documented at hedge inception in accordance with the Company’s accounting policy election. Amounts reported in accumulated OCI related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt.
Investments in Unconsolidated Affiliates	Investments in Unconsolidated Affiliates Investments in unconsolidated affiliates in which the Company exerts significant influence but does not control or otherwise consolidate are accounted for using the equity method. Equity method investments are initially recorded at cost, unless the investments are a result of the Company losing control of a previously controlled entity, but still retaining a non-controlling interest. Transactions that result in the deconsolidation of a previously consolidated entity, are measured at fair value. The fair value measurement utilizes Level 3 inputs, which include unobservable data, to measure the fair value of the retained non-controlling interest. The fair value determination is generally based on a combination of multiple valuation methods, which can include discounted cash flow, income approach, or market value approach which incorporates estimates of future earnings and market valuation multiples for certain guideline companies. These investments are included as investments in and advances to affiliates in the accompanying consolidated balance sheets. The Company’s share of the profits and losses from these investments is reported in income from equity investments in the accompanying consolidated statements of operations. The Company monitors its investments for other-than-temporary impairment by considering factors such as current economic and market conditions and the operating performance of the investees and records reductions in carrying values when necessary.
Non-Controlling Interests	Non-Controlling Interests The physician limited partners and physician minority members of the entities that the Company controls are responsible for the supervision and delivery of medical services. The governance rights of limited partners and minority members are restricted to those that protect their financial interests. Under certain partnership and operating agreements governing these partnerships and limited liability companies, the Company could be removed as the sole general partner or managing member for certain events such as material breach of the partnership or operating agreement, gross negligence or bankruptcy. These protective rights do not preclude consolidation of the respective partnerships and limited liability companies. Ownership interests in consolidated subsidiaries held by parties other than the Company are identified and generally presented in the consolidated financial statements within the equity section but separate from the Company's equity. However, in instances in which certain redemption features that are not solely within the control of the Company are present, classification of non-controlling interests outside of permanent equity is required. Consolidated net income attributable to the Company and to the non-controlling interests are identified and presented on the consolidated statements of operations; changes in ownership interests in which the Company retains a controlling interest are accounted for as equity transactions assuming the Company continues to consolidate related entities. Certain transactions with non-controlling interests are classified within financing activities in the consolidated statements of cash flows. The consolidated financial statements of the Company include all assets, liabilities, revenues and expenses of surgical facilities in which the Company has sufficient ownership and rights to allow the Company to consolidate the surgical facilities. Similar to its investments in non-consolidated affiliates, the Company regularly engages in the purchase and sale of ownership interests with respect to its consolidated subsidiaries that do not result in a change of control. Non-Controlling Interests — Redeemable. Each partnership and limited liability company through which the Company owns and operates its surgical facilities is governed by a partnership or operating agreement, respectively. In certain circumstances, the applicable partnership or operating agreements for the Company's surgical facilities provide that the facilities will purchase all of the physician limited partners’ or physician minority members’, as applicable, ownership if certain adverse regulatory events occur, such as it becoming illegal for the physician(s) to own an interest in a surgical facility, refer patients to a surgical facility or receive cash distributions from a surgical facility. The non-controlling interests—redeemable are reported outside of stockholders' equity in the consolidated balance sheets.
Inventories	Inventories Inventories, which consist primarily of medical and drug supplies, are stated at the lower of cost or market value. Cost is determined using the first-in, first-out method.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2020, the FASB issued Accounting Standards Update (“ASU”) 2020-04 Reference Rate Reform (Topic 848). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the year ended December 31, 2020, the Company elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future London Interbank Offered Rate ("LIBOR") indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, which introduced a new model for recognizing credit losses on financial instruments based on an estimate of the current expected credit losses. The new current expected credit losses (“CECL”) model generally calls for the immediate recognition of all expected credit losses and applies to financial instruments and other assets, which is primarily applicable to accounts receivable for the Company. This ASU was effective for the Company on January 1, 2020. The adoption of this ASU did not have a material impact on its consolidated financial position and results of operations. In February 2016, the FASB issued ASU 2016-02, "Leases" (the "Lease Accounting Standard"). The Company adopted the Lease Accounting Standard effective January 1, 2019, using a modified retrospective transition approach. The most prominent of the changes resulting from this ASU is the recognition of right-of-use assets and lease liabilities by lessees for those leases classified as operating leases. The Company’s accounting for finance leases remained substantially unchanged from its prior accounting for capital leases. Upon adoption of the Lease Accounting Standard, the Company recorded $294.0 million of operating lease liabilities and right-of-use assets on January 1, 2019. The cumulative effect of the accounting change recognized upon adoption was $6.1 million reflected as an adjustment to retained deficit in our consolidated balance sheets.
Acquisitions and Disposals	Acquisitions and Disposals The Company accounts for business combinations in accordance with the fundamental requirements of the acquisition method of accounting and under the premise that an acquirer can be identified for each business combination. The acquirer is the entity that obtains control of one or more businesses in the business combination and the acquisition date is the date the acquirer achieves control. The assets acquired, liabilities assumed and any non-controlling interests in the acquired business at the acquisition date are recognized at their fair values as of that date, and the direct costs incurred in connection with the business combination are recorded and expensed separately from the business combination. Any goodwill recognized is determined as the excess of the fair value of the consideration conveyed plus the fair value of any non-controlling interests in the acquisition over the fair value of the net assets acquired. Acquisitions in which the Company is able to exert significant influence but does not have control are accounted for using the equity method. Acquired assets and assumed liabilities typically include, but are not limited to, fixed assets, intangible assets and right-of-use leases. The valuations are based on appraisal reports, discounted cash flow analyses, actuarial analyses or other appropriate valuation techniques to determine the fair value of the assets acquired or liabilities assumed. Fair value attributable to non-controlling interests is based on a Level 3 computation using significant inputs that are not observable in the market. Key inputs used to determine the fair value include financial multiples used in the purchase of non-controlling interests, primarily from acquisitions of surgical facilities. Such multiples, based on earnings, are used as a benchmark for the discount to be applied for the lack of control or marketability. Fair value attributable to the property and equipment acquired is based on Level 3 computations using key inputs such as cost trend data and comparable asset sales. Fair value attributable to the intangible assets acquired is based on Level 3 computations using key inputs such as the Company's internally-prepared financial projections. Fair values assigned to acquired working capital are based on carrying amounts reported by the acquiree at the date of acquisition, which approximate their fair values.
Property and Equipment	Property and EquipmentProperty and equipment are stated at cost or, if obtained through acquisition, at fair value determined on the date of acquisition. Depreciation is recognized using the straight-line method over the estimated useful lives of the assets, generally 20 to 40 years for buildings and building improvements, three to five years for computers and software and five to seven years for furniture and equipment. Leasehold improvements are depreciated on a straight-line basis over the shorter of the lease term or the estimated useful life of the assets. Routine maintenance and repairs are expensed as incurred, while expenditures that increase capacities or extend useful lives are capitalized. The Company also leases certain facilities and equipment under finance leases. Assets held under finance leases are stated at the present value of lease payments at the inception of the related lease. Such assets are amortized on a straight-line basis over the lesser of the lease term or the remaining useful life of the leased asset.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill represents the fair value of the consideration provided in an acquisition over the fair value of net assets acquired and is not amortized. The Company has indefinite-lived intangible assets related to the certificates of need held in jurisdictions where certain of its surgical facilities are located, Medicare licenses and certain management rights agreements. The Company also has finite-lived intangible assets related to physician guarantee agreements, non-compete agreements, management rights agreements and customer relationships. Physician income guarantees are amortized into salaries and benefits costs in the consolidated statements of operations over the commitment period of the contract, generally three to four years. Non-compete agreements and management rights agreements are amortized into depreciation and amortization expense in the consolidated statements of operations over the service lives of the agreements, typically ranging from two to five years for non-compete agreements and 15 years for the management rights agreements. Customer relationships are amortized into depreciation and amortization expense in the consolidated statements of operations over the estimated lives of the relationships, ranging from three to ten years. The Company tests its goodwill and indefinite-lived intangible assets for impairment at least annually, as of October 1, or more frequently if certain indicators arise. The Company tests for goodwill impairment at the reporting unit level, which is defined as one level below an operating segment. During 2020, the Company identified three reporting units, which include the following: 1) Surgical Facilities, 2) Ancillary Services, and 3) Alliance, which is a component of the Optical Services operating segment. A detailed evaluation of potential impairment indicators was performed, which specifically considered the volatility observed in the prices of the Company’s outstanding debt securities and common stock, as well as the decline in surgical case volumes following the emergence of the COVID-19 pandemic, all of which improved in the second half of 2020 as states began to re-open and allow for non-emergent procedures. The Company compares the carrying value of the net assets of the reporting unit to the estimated fair value of the reporting unit. To determine the fair value of the reporting units, the Company obtained valuations at the reporting unit level prepared by third-party valuation specialists which typically utilizes a combination of the income and market approaches. The discounted cash flow model is projected based on a year-by-year assessment that considers historical results, estimated market conditions, internal projections, and relevant publicly available statistics. Determining fair value requires the exercise of significant judgment, including assumptions about appropriate discount rates, perpetual growth rates and the amount and timing of expected future cash flows. The significant judgments are typically based upon Level 3 inputs, generally defined as unobservable inputs representing the Company's own assumptions. The cash flows employed in the discounted cash flow analysis are based on the Company's most recent budgets and business plans aligned with provided guidance and, when applicable, various growth rates are assumed for years beyond the current business plan period. Discount rate assumptions are based on an assessment of the risk inherent in the future cash flows of the respective reporting units. The variables within the discount rate, many of which are outside of the Company's control, provide the best estimate of all assumptions applied within the discounted cash flow model. There can be no assurance that operations will achieve the future cash flows reflected in the projections. In determining the fair value under the market approaches, the analysis includes a control premium, which was based on observable market data and a review of selected transactions of companies that operate in the Company's sector. While the Company believes that all assumptions utilized in the testing were appropriate, they may not reflect actual outcomes that could occur. Specific factors that could negatively impact the assumptions used include changes to the discount and growth rates and a change in the equity and enterprise premiums being realized in the market.
Leases	LeasesThe Company determines if an arrangement is a lease at inception. Right-of-use assets represent the right to use the underlying assets for the lease term and the lease liabilities represent the obligation to make lease payments arising from the leases. Right-of-use assets and liabilities are recognized at commencement date based on the present value of future lease payments over the lease term, which includes only payments that are fixed and determinable at the time of commencement. When readily determinable, the Company uses the interest rate implicit in a lease to determine the present value of future lease payments. For leases where the implicit rate is not readily determinable, the Company's incremental borrowing rate is used. The Company calculates its incremental borrowing rate on a periodic basis using a third-party financial model that estimates the rate of interest the Company would have to pay to borrow an amount equal to the total lease payments on a collateralized basis over a term similar to the lease. The Company applies its incremental borrowing rate using a portfolio approach. The right-of-use asset also includes any lease payments made prior to commencement and is recorded net of any lease incentives received. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options. The Company's operating leases are primarily for real estate, including medical office buildings, and corporate and other administrative offices. The Company's finance leases are primarily for medical equipment and information technology and telecommunications assets. The Company's finance leases also include certain land, buildings and improvements as discussed in Note 3. "Property and Equipment." Real estate lease agreements typically have initial terms of ten years and may include one or more options to renew. Certain leases also include options to purchase the leased property. The useful life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. The majority of the Company's medical equipment leases have a bargain purchase option that is reasonably certain of exercise, so these assets are depreciated over their useful life. The Company's lease agreements do not contain any material residual value guarantees, restrictions or covenants. Certain of the Company's lease agreements require the Company to pay common area maintenance, repairs, property taxes and insurance costs, which are variable amounts based on actual costs incurred during each applicable period. Certain lease agreements also include escalating rent payments that are not fixed at commencement but are based on an index that is determined in future periods over the lease term based on changes in the Consumer Price Index or other measure of cost inflation. These variable components of lease payments are expensed as incurred and are not included in the determination of the right-of-use asset or lease liability. Due to the COVID-19 pandemic, the Company received concessions for certain of its leases primarily consisting of deferral of rental payments. The Company has elected to account for these COVID-19 related concessions as though the enforceable rights and obligations for those concessions are explicit within the underlying contract. The Company accounts for the deferred rentals as a component of other current liabilities within the consolidated balance sheets. In a few instances the Company modified the terms of the lease in exchange for lease concessions. These modifications resulted in an increase to the Company's right-of-use operating lease assets and liabilities of $27.4 million during the year ended December 31, 2020.
Earnings Per Share	Earnings Per ShareBasic and diluted earnings per share are calculated based on the weighted-average number of shares outstanding in each period and dilutive stock options, unvested shares and warrants, to the extent such securities exist and have a dilutive effect on earnings per share. The Company computes basic and diluted earnings per share using the two-class method. The two-class method of computing earnings per share is an earnings allocation method that determines earnings per share for common shares and participating securities according to their participation rights in dividends and undistributed earnings.
Income Taxes	Income Taxes The Company uses the asset and liability method to account for income taxes. Under this method, deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Any change in tax rates that could impact deferred tax assets or liabilities are recognized in the same period the change occurs. If a net operating loss ("NOL") and/or interest limitation ("163(j)") carryforward exists, the Company makes a determination as to whether that NOL and/or 163(j) carryforward will be utilized in the future. A valuation allowance is established for certain net operating loss and interest limitation carryforwards when their recoverability is deemed to be uncertain. The carrying value of the net deferred tax assets assumes that the Company will be able to generate sufficient future taxable income in certain tax jurisdictions, based on estimates and assumptions. If these estimates and related assumptions change in the future, the Company may be required to adjust its deferred tax valuation allowances. The Company, or one or more of its subsidiaries, files income tax returns in the U.S. federal jurisdiction and various state jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal income tax examinations for years prior to 2017 or state income tax examinations for years prior to 2016. The Company and certain of its subsidiaries file a consolidated federal income tax return. The partnerships, limited liability companies, and certain non-consolidated physician practice corporations also file separate income tax returns. The Company's allocable portion of each partnership's and limited liability company's income or loss is included in taxable income of the Company. The remaining income or loss of each partnership and limited liability company is allocated to the other owners.
Equity-Based Compensation	Equity-Based CompensationTransactions in which the Company receives employee and non-employee services in exchange for the Company’s equity instruments or liabilities that are based on the fair value of the Company’s equity securities or may be settled by the issuance of these securities are accounted for using a fair value method. The Company’s policy is to recognize compensation expense using the straight line method over the relevant vesting period for units that vest based on time.

Organization and Summary of Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The preparation of financial statements in conformity with generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and footnotes. Examples include, but are not limited to, estimates of accounts receivable allowances, professional and general liabilities and the estimate of deferred tax assets or liabilities. Actual results could differ from those estimates.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, as well as interests in partnerships and limited liability companies controlled by the Company through its ownership of a majority voting interest or other rights granted to the Company by contract to manage and control the affiliate's business. All significant intercompany balances and transactions are eliminated in consolidation.

Variable Interest Entities

The consolidated financial statements include the accounts of variable interest entities ("VIE") in which the Company is the primary beneficiary under the provisions of Accounting Standards Codification 810, Consolidation. The Company has the power to direct the activities that most significantly impact a variable interest entity's economic performance. Additionally, the Company would absorb the majority of the expected losses from any of these entities should such expected losses occur. At December 31, 2020, the variable interest entities include four surgical facilities and three physician practices.

Fair Value of Financial Instruments

The fair value of a financial instrument is the amount at which the instrument could be exchanged in an orderly transaction between market participants to sell the asset or transfer the liability. The Company uses fair value measurements based on inputs classified into the following hierarchy:

•Level 1: Unadjusted quoted prices in active markets for identical assets or liabilities.

•Level 2: Inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly. These may include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active.

•Level 3: Unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions, depending on the nature of the item being valued.

The carrying amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, restricted invested assets and accounts payable approximate their fair values under Level 3 calculations.

The fair values in the table above were based on a Level 2 inputs using quoted prices for identical liabilities in inactive markets. The carrying amounts related to the Company's other long-term debt obligations, including finance lease obligations, approximate their fair values under Level 3 calculations.The fair value of these derivative financial instruments was based on a quoted market price, or a Level 2 input.

Revenues

The Company's revenues generally relate to contracts with patients in which the performance obligations are to provide health care services. The Company recognizes revenues in the period in which our obligations to provide health care services are satisfied and reports the amount that reflects the consideration the Company expects to be entitled to receive. The contractual relationships with patients, in most cases, also involve a third-party payor (e.g., Medicare, Medicaid and private insurance organizations, including plans offered through the health insurance exchanges) and the transaction prices for the services provided are dependent upon the terms provided by or negotiated with the third-party payors. The payment arrangements with third-party payors for the services provided to the related patients typically specify payments at amounts less than the Company's standard charges. The Company continually reviews the contractual estimation process to consider and incorporate updates to laws and regulations and the frequent changes in managed care contractual terms resulting from contract renegotiations and renewals.

Patient service revenues. This revenue is related to charging facility fees in exchange for providing patient care. The fee charged for health care procedures performed in surgical facilities varies depending on the type of service provided, but usually includes all charges for usage of an operating room, a recovery room, special equipment, medical supplies, nursing staff and medications. The fee does not normally include professional fees charged by the patient’s surgeon, anesthesiologist or other attending physician, which are billed directly by such physicians to the patient or third-party payor. However, in several surgical facilities, the Company charges for anesthesia services.

Ancillary service revenues include fees for patient visits to the Company's physician practices, pharmacy services and diagnostic tests ordered by physicians.

Patient service revenues are recognized as performance obligations are satisfied. Performance obligations are based on the nature of services provided. Typically, the Company recognizes revenue at a point in time in which services are rendered and the Company has no obligation to provide further patient services. As the Company primarily performs outpatient procedures, performance obligations are generally satisfied same day and revenue is recognized on the date of service.

The Company determines the transaction price based on gross charges for services provided, net of estimated contractual adjustments, discounts from third-party payors. The Company estimates its contractual adjustments and discounts based on contractual agreements, its discount policies and historical experience. Changes in estimated contractual adjustments and discounts are recorded in the period of change.

Other service revenues. Optical service revenues consist of handling charges billed to the members of the Company's optical products purchasing organization. The Company's optical products purchasing organization negotiates volume buying discounts with optical products manufacturers. The buying discounts and any handling charges billed to the members of the buying group represent the revenue recognized for financial reporting purposes. The Company satisfies the performance obligation and recognizes revenue when the orders are shipped to members. The Company bases its estimates for sales returns and discounts on historical experience and has not experienced significant fluctuations between estimated and actual return activity and discounts given. The Company sold its optical products purchasing organization on December 31, 2020.

Other revenues include management and administrative service fees derived from the non-consolidated facilities that the Company accounts for under the equity method, management of surgical facilities in which it does not own an interest, and management services provided to physician practices for which the Company is not required to provide capital or additional assets. These agreements typically require the Company to provide recurring management services over a multi-year period which are billed and collected on a monthly basis. The fees derived from these management arrangements are based on a predetermined percentage of the revenues of each facility or practice and are recognized in the period in which management services are rendered and billed.

Cash, Cash Equivalents and Restricted Cash

The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company maintains its cash and cash equivalent balances at high credit quality financial institutions.

Cash, cash equivalents and restricted cash reported within the consolidated statement of cash flows includes $0.3 million of restricted investments, which are reflected in other long-term assets in the consolidated balance sheet at both December 31, 2020 and 2019. These restricted investments represent restricted cash held in accordance with the provisions of a long-term operating lease agreement held as security for performance under the Company's covenants and obligations within the agreement through January 2024.

Accounts Receivable

Accounts receivable from third-party payors are recorded net of estimated implicit price concessions, which are estimated based on the historical trend of the Company's surgical hospitals’ cash collections and contractual write-offs, and for the Company's surgical facilities in general, established fee schedules, relationships with payors and procedure statistics. While changes in estimated reimbursement from

third-party payors remain a possibility, the Company expects that any such changes would be minimal and, therefore, would not have a material effect on its financial condition or results of operations.

Accounts receivable consists of receivables from federal and state agencies (under the Medicare and Medicaid programs), private insurance organizations, employers and patients. Management recognizes that revenues and receivables from government agencies are significant to the Company's operations, but it does not believe that there is significant credit risk associated with these government agencies. Concentration of credit risk with respect to other payors is limited because of the large number of such payors.

The Company recognizes that final reimbursement of accounts receivable is subject to final approval by each third-party payor. However, because the Company has contracts with its third-party payors and also verifies insurance coverage of the patient before medical services are rendered, the amounts that are pending approval from third-party payors are not considered significant. Amounts are classified outside of self-pay if the Company has an agreement with the third-party payor or has verified a patient’s coverage prior to services rendered. The Company's policy is to collect co-payments and deductibles prior to providing medical services. Patient services of the Company are primarily non-emergency, which allows the surgical facilities to control the procedures for which third-party reimbursement is sought and obtained. The Company does not require collateral from self-pay patients.

The Company's collection policies and procedures are based on the type of payor, size of claim and estimated collection percentage for each patient account. The Company analyzes accounts receivable at each of its surgical facilities to ensure the proper collection and aged category. Collection efforts include direct contact with third-party payors or patients, written correspondence and the use of legal or collection agency assistance, as required.

Impairment of Long-Lived Assets, Goodwill and Intangible Assets

The Company evaluates the carrying value of long-lived assets when impairment indicators are present or when circumstances indicate that impairment may exist. The Company performs an impairment test by preparing an expected undiscounted cash flow projection. If the projection indicates that the recorded amount of the long-lived asset is not expected to be recovered, the carrying value is reduced to estimated fair value. The cash flow projection and fair value represents management’s best estimate, using appropriate and customary assumptions, projections and methodologies, at the date of evaluation. For discussion on impairment for goodwill and indefinite-lived intangible assets, refer to Note 4. "Goodwill and Intangible Assets."

Professional and General and Workers' Compensation Insurance

The Company maintains general liability and professional liability insurance in excess of self-insured retentions through third party commercial insurance carriers in amounts that management believes is sufficient for the Company's operations, although, potentially, some claims may exceed the scope of coverage in effect. The professional liability insurance coverage is on a claims-made basis and the general liability insurance is on an occurrence basis. The Company also maintains workers' compensation insurance, subject to a self-insured retention.

The Company expenses the costs under the self-insured retention exposure for general and professional liability and workers' compensation claims which relate to (i) claims made during the policy period, which are offset by insurance recoveries and (ii) an estimate of claims incurred but not yet reported that are expected to be reported after the policy period expires. Reserves and provisions are based upon actuarially determined estimates using individual case-basis valuations and actuarial analysis. Reserves for professional, general and workers' compensation claim liabilities are determined with no regard for expected insurance recoveries and are presented gross on the consolidated balance sheets.

Derivative Instruments and Hedging Activities

The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting.

The Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio.

Derivatives and Hedging ActivitiesThe Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps as part of its interest rate risk management strategy. During 2020 and 2019, such derivatives have been used to hedge the variable cash flows associated with existing variable-rate debt. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive income ("OCI") and subsequently reclassified into interest expense in the same period(s) during which the hedged transaction affects earnings, as documented at hedge inception in accordance with the Company’s accounting policy election. Amounts reported in accumulated OCI related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt.

Investments in Unconsolidated Affiliates

Investments in unconsolidated affiliates in which the Company exerts significant influence but does not control or otherwise consolidate are accounted for using the equity method. Equity method investments are initially recorded at cost, unless the investments are a result of the Company losing control of a previously controlled entity, but still retaining a non-controlling interest. Transactions that result in the deconsolidation of a previously consolidated entity, are measured at fair value. The fair value measurement utilizes Level 3 inputs,

which include unobservable data, to measure the fair value of the retained non-controlling interest. The fair value determination is generally based on a combination of multiple valuation methods, which can include discounted cash flow, income approach, or market value approach which incorporates estimates of future earnings and market valuation multiples for certain guideline companies. These investments are included as investments in and advances to affiliates in the accompanying consolidated balance sheets. The Company’s share of the profits and losses from these investments is reported in income from equity investments in the accompanying consolidated statements of operations. The Company monitors its investments for other-than-temporary impairment by considering factors such as current economic and market conditions and the operating performance of the investees and records reductions in carrying values when necessary.

Non-Controlling Interests

The physician limited partners and physician minority members of the entities that the Company controls are responsible for the supervision and delivery of medical services. The governance rights of limited partners and minority members are restricted to those that protect their financial interests. Under certain partnership and operating agreements governing these partnerships and limited liability companies, the Company could be removed as the sole general partner or managing member for certain events such as material breach of the partnership or operating agreement, gross negligence or bankruptcy. These protective rights do not preclude consolidation of the respective partnerships and limited liability companies.

Ownership interests in consolidated subsidiaries held by parties other than the Company are identified and generally presented in the consolidated financial statements within the equity section but separate from the Company's equity. However, in instances in which certain redemption features that are not solely within the control of the Company are present, classification of non-controlling interests outside of permanent equity is required. Consolidated net income attributable to the Company and to the non-controlling interests are identified and presented on the consolidated statements of operations; changes in ownership interests in which the Company retains a controlling interest are accounted for as equity transactions assuming the Company continues to consolidate related entities. Certain transactions with non-controlling interests are classified within financing activities in the consolidated statements of cash flows.

The consolidated financial statements of the Company include all assets, liabilities, revenues and expenses of surgical facilities in which the Company has sufficient ownership and rights to allow the Company to consolidate the surgical facilities. Similar to its investments in non-consolidated affiliates, the Company regularly engages in the purchase and sale of ownership interests with respect to its consolidated subsidiaries that do not result in a change of control.

Non-Controlling Interests — Redeemable. Each partnership and limited liability company through which the Company owns and operates its surgical facilities is governed by a partnership or operating agreement, respectively. In certain circumstances, the applicable partnership or operating agreements for the Company's surgical facilities provide that the facilities will purchase all of the physician limited partners’ or physician minority members’, as applicable, ownership if certain adverse regulatory events occur, such as it becoming illegal for the physician(s) to own an interest in a surgical facility, refer patients to a surgical facility or receive cash distributions from a surgical facility. The non-controlling interests—redeemable are reported outside of stockholders' equity in the consolidated balance sheets.

Inventories

Inventories, which consist primarily of medical and drug supplies, are stated at the lower of cost or market value. Cost is determined using the first-in, first-out method.

Recent Accounting Pronouncements

In March 2020, the FASB issued Accounting Standards Update (“ASU”) 2020-04 Reference Rate Reform (Topic 848). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the year ended December 31, 2020, the Company elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future London Interbank Offered Rate ("LIBOR") indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of

derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, which introduced a new model for recognizing credit losses on financial instruments based on an estimate of the current expected credit losses. The new current expected credit losses (“CECL”) model generally calls for the immediate recognition of all expected credit losses and applies to financial instruments and other assets, which is primarily applicable to accounts receivable for the Company. This ASU was effective for the Company on January 1, 2020. The adoption of this ASU did not have a material impact on its consolidated financial position and results of operations.

In February 2016, the FASB issued ASU 2016-02, "Leases" (the "Lease Accounting Standard"). The Company adopted the Lease Accounting Standard effective January 1, 2019, using a modified retrospective transition approach. The most prominent of the changes resulting from this ASU is the recognition of right-of-use assets and lease liabilities by lessees for those leases classified as operating leases. The Company’s accounting for finance leases remained substantially unchanged from its prior accounting for capital leases. Upon adoption of the Lease Accounting Standard, the Company recorded $294.0 million of operating lease liabilities and right-of-use assets on January 1, 2019. The cumulative effect of the accounting change recognized upon adoption was $6.1 million reflected as an adjustment to retained deficit in our consolidated balance sheets.

Acquisitions and Disposals

The Company accounts for business combinations in accordance with the fundamental requirements of the acquisition method of accounting and under the premise that an acquirer can be identified for each business combination. The acquirer is the entity that obtains control of one or more businesses in the business combination and the acquisition date is the date the acquirer achieves control. The assets acquired, liabilities assumed and any non-controlling interests in the acquired business at the acquisition date are recognized at their fair values as of that date, and the direct costs incurred in connection with the business combination are recorded and expensed separately from the business combination. Any goodwill recognized is determined as the excess of the fair value of the consideration conveyed plus the fair value of any non-controlling interests in the acquisition over the fair value of the net assets acquired. Acquisitions in which the Company is able to exert significant influence but does not have control are accounted for using the equity method.

Acquired assets and assumed liabilities typically include, but are not limited to, fixed assets, intangible assets and right-of-use leases. The valuations are based on appraisal reports, discounted cash flow analyses, actuarial analyses or other appropriate valuation techniques to determine the fair value of the assets acquired or liabilities assumed. Fair value attributable to non-controlling interests is based on a Level 3 computation using significant inputs that are not observable in the market. Key inputs used to determine the fair value include financial multiples used in the purchase of non-controlling interests, primarily from acquisitions of surgical facilities. Such multiples, based on earnings, are used as a benchmark for the discount to be applied for the lack of control or marketability. Fair value attributable to the property and equipment acquired is based on Level 3 computations using key inputs such as cost trend data and comparable asset sales. Fair value attributable to the intangible assets acquired is based on Level 3 computations using key inputs such as the Company's internally-prepared financial projections. Fair values assigned to acquired working capital are based on carrying amounts reported by the acquiree at the date of acquisition, which approximate their fair values.

Property and Equipment

Property and EquipmentProperty and equipment are stated at cost or, if obtained through acquisition, at fair value determined on the date of acquisition. Depreciation is recognized using the straight-line method over the estimated useful lives of the assets, generally 20 to 40 years for buildings

and building improvements, three to five years for computers and software and five to seven years for furniture and equipment. Leasehold improvements are depreciated on a straight-line basis over the shorter of the lease term or the estimated useful life of the assets. Routine maintenance and repairs are expensed as incurred, while expenditures that increase capacities or extend useful lives are capitalized.

The Company also leases certain facilities and equipment under finance leases. Assets held under finance leases are stated at the present value of lease payments at the inception of the related lease. Such assets are amortized on a straight-line basis over the lesser of the lease term or the remaining useful life of the leased asset.

Goodwill and Intangible Assets

Goodwill represents the fair value of the consideration provided in an acquisition over the fair value of net assets acquired and is not amortized. The Company has indefinite-lived intangible assets related to the certificates of need held in jurisdictions where certain of its surgical facilities are located, Medicare licenses and certain management rights agreements. The Company also has finite-lived intangible assets related to physician guarantee agreements, non-compete agreements, management rights agreements and customer relationships. Physician income guarantees are amortized into salaries and benefits costs in the consolidated statements of operations over the commitment period of the contract, generally three to four years. Non-compete agreements and management rights agreements are amortized into depreciation and amortization expense in the consolidated statements of operations over the service lives of the agreements, typically ranging from two to five years for non-compete agreements and 15 years for the management rights agreements. Customer relationships are amortized into depreciation and amortization expense in the consolidated statements of operations over the estimated lives of the relationships, ranging from three to ten years.

The Company tests its goodwill and indefinite-lived intangible assets for impairment at least annually, as of October 1, or more frequently if certain indicators arise. The Company tests for goodwill impairment at the reporting unit level, which is defined as one level below an operating segment. During 2020, the Company identified three reporting units, which include the following: 1) Surgical Facilities, 2) Ancillary Services, and 3) Alliance, which is a component of the Optical Services operating segment. A detailed evaluation of potential impairment indicators was performed, which specifically considered the volatility observed in the prices of the Company’s outstanding debt securities and common stock, as well as the decline in surgical case volumes following the emergence of the COVID-19 pandemic, all of which improved in the second half of 2020 as states began to re-open and allow for non-emergent procedures.

The Company compares the carrying value of the net assets of the reporting unit to the estimated fair value of the reporting unit. To determine the fair value of the reporting units, the Company obtained valuations at the reporting unit level prepared by third-party valuation specialists which typically utilizes a combination of the income and market approaches. The discounted cash flow model is projected based on a year-by-year assessment that considers historical results, estimated market conditions, internal projections, and relevant publicly available statistics. Determining fair value requires the exercise of significant judgment, including assumptions about appropriate discount rates, perpetual growth rates and the amount and timing of expected future cash flows. The significant judgments are typically based upon Level 3 inputs, generally defined as unobservable inputs representing the Company's own assumptions. The cash flows employed in the discounted cash flow analysis are based on the Company's most recent budgets and business plans aligned with provided guidance and, when applicable, various growth rates are assumed for years beyond the current business plan period. Discount rate assumptions are based on an assessment of the risk inherent in the future cash flows of the respective reporting units. The variables within the discount rate, many of which are outside of the Company's control, provide the best estimate of all assumptions applied within the discounted cash flow model. There can be no assurance that operations will achieve the future cash flows reflected in the projections. In determining the fair value under the market approaches, the analysis includes a control premium, which was based on observable market data and a review of selected

transactions of companies that operate in the Company's sector. While the Company believes that all assumptions utilized in the testing were appropriate, they may not reflect actual outcomes that could occur. Specific factors that could negatively impact the assumptions used include changes to the discount and growth rates and a change in the equity and enterprise premiums being realized in the market.

Leases

LeasesThe Company determines if an arrangement is a lease at inception. Right-of-use assets represent the right to use the underlying assets for the lease term and the lease liabilities represent the obligation to make lease payments arising from the leases. Right-of-use assets and liabilities are recognized at commencement date based on the present value of future lease payments over the lease term, which includes

only payments that are fixed and determinable at the time of commencement. When readily determinable, the Company uses the interest rate implicit in a lease to determine the present value of future lease payments. For leases where the implicit rate is not readily determinable, the Company's incremental borrowing rate is used. The Company calculates its incremental borrowing rate on a periodic basis using a third-party financial model that estimates the rate of interest the Company would have to pay to borrow an amount equal to the total lease payments on a collateralized basis over a term similar to the lease. The Company applies its incremental borrowing rate using a portfolio approach. The right-of-use asset also includes any lease payments made prior to commencement and is recorded net of any lease incentives received. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options.

The Company's operating leases are primarily for real estate, including medical office buildings, and corporate and other administrative offices. The Company's finance leases are primarily for medical equipment and information technology and telecommunications assets. The Company's finance leases also include certain land, buildings and improvements as discussed in Note 3. "Property and Equipment." Real estate lease agreements typically have initial terms of ten years and may include one or more options to renew. Certain leases also include options to purchase the leased property. The useful life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. The majority of the Company's medical equipment leases have a bargain purchase option that is reasonably certain of exercise, so these assets are depreciated over their useful life. The Company's lease agreements do not contain any material residual value guarantees, restrictions or covenants.

Certain of the Company's lease agreements require the Company to pay common area maintenance, repairs, property taxes and insurance costs, which are variable amounts based on actual costs incurred during each applicable period. Certain lease agreements also include escalating rent payments that are not fixed at commencement but are based on an index that is determined in future periods over the lease term based on changes in the Consumer Price Index or other measure of cost inflation. These variable components of lease payments are expensed as incurred and are not included in the determination of the right-of-use asset or lease liability.

Due to the COVID-19 pandemic, the Company received concessions for certain of its leases primarily consisting of deferral of rental payments. The Company has elected to account for these COVID-19 related concessions as though the enforceable rights and obligations for those concessions are explicit within the underlying contract. The Company accounts for the deferred rentals as a component of other current liabilities within the consolidated balance sheets. In a few instances the Company modified the terms of the lease in exchange for lease concessions. These modifications resulted in an increase to the Company's right-of-use operating lease assets and liabilities of $27.4 million during the year ended December 31, 2020.

Earnings Per Share

Earnings Per ShareBasic and diluted earnings per share are calculated based on the weighted-average number of shares outstanding in each period and dilutive stock options, unvested shares and warrants, to the extent such securities exist and have a dilutive effect on earnings per share. The Company computes basic and diluted earnings per share using the two-class method. The two-class method of computing earnings per share is an earnings allocation method that determines earnings per share for common shares and participating securities according to their participation rights in dividends and undistributed earnings.

Income Taxes

The Company uses the asset and liability method to account for income taxes. Under this method, deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Any change in tax rates that could impact deferred tax assets or liabilities are recognized in the same period the change occurs. If a net operating loss ("NOL") and/or interest limitation ("163(j)") carryforward exists, the Company makes a determination as to whether that NOL and/or 163(j) carryforward will be utilized in the future. A valuation allowance is established for certain net operating loss and interest limitation carryforwards when their recoverability is deemed to be uncertain. The carrying value of the net deferred tax assets assumes that the Company will be able to generate sufficient future taxable income in certain tax jurisdictions, based on estimates and assumptions. If these estimates and related assumptions change in the future, the Company may be required to adjust its deferred tax valuation allowances.

The Company, or one or more of its subsidiaries, files income tax returns in the U.S. federal jurisdiction and various state jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal income tax examinations for years prior to 2017 or state income tax examinations for years prior to 2016.

The Company and certain of its subsidiaries file a consolidated federal income tax return. The partnerships, limited liability companies, and certain non-consolidated physician practice corporations also file separate income tax returns. The Company's allocable portion of each partnership's and limited liability company's income or loss is included in taxable income of the Company. The remaining income or loss of each partnership and limited liability company is allocated to the other owners.

Equity-Based Compensation

Equity-Based CompensationTransactions in which the Company receives employee and non-employee services in exchange for the Company’s equity instruments or liabilities that are based on the fair value of the Company’s equity securities or may be settled by the issuance of these securities are accounted for using a fair value method. The Company’s policy is to recognize compensation expense using the straight line method over the relevant vesting period for units that vest based on time.