Condensed consolidated interim financial statements (Policies)	9 Months Ended
	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Condensed consolidated interim financial statements	The condensed consolidated interim financial statements included in this report are prepared by the Company without audit. In the opinion of management, all adjustments necessary for a fair presentation of the results of operations are reflected in these consolidated interim financial statements. All significant intercompany accounts and transactions have been eliminated. The preparation of these financial statements requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. The most significant estimates and assumptions underlying these financial statements and accompanying notes generally involve revenue recognition and accounts receivable, contingencies, impairments of goodwill and other long-lived assets, fair value estimates, accounting for income taxes, variable compensation accruals, consolidation of variable interest entities, purchase accounting valuation estimates, long-term incentive program compensation and medical liability claims. The results of operations for the nine months ended September 30, 2016 are not necessarily indicative of the operating results for the full year. The condensed consolidated interim financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. Prior year balances and amounts have been reclassified to conform to the current year presentation. The Company has evaluated subsequent events through the date these condensed consolidated financial statements were issued and has included all necessary adjustments and disclosures.
Earnings per share	Basic net income per share is calculated by dividing net income attributable to the Company, adjusted for any change in noncontrolling interests redemption rights in excess of fair value, by the weighted average number of common shares and vested stock units outstanding, net of shares held in escrow that under certain circumstances may be returned to the Company. Diluted net income per share includes the dilutive effect of outstanding stock-settled stock appreciation rights and unvested stock units (under the treasury stock method) as well as contingently returnable shares held in escrow.
Accounts receivable	Accounts receivable are reduced by an allowance for doubtful accounts. In evaluating the ultimate collectability of accounts receivable, the Company analyzes its historical cash collection experience and trends for each of its government payors and commercial payors to estimate the adequacy of the allowance for doubtful accounts and the amount of the provision for uncollectible accounts. Management regularly updates its analysis based upon the most recent information available to determine its current provision for uncollectible accounts and the adequacy of its allowance for doubtful accounts. For receivables associated with dialysis patient services covered by Medicare, the Company receives 80% of the payment directly from Medicare as established under the government’s bundled payment system and determines an appropriate allowance for doubtful accounts and provision for uncollectible accounts on the remaining balance due depending upon the Company’s estimate of the amounts ultimately collectible from other secondary coverage sources or from the patients. For receivables associated with services to patients covered by commercial payors that are either based upon contractual terms or for non-contracted health plan coverage, the Company provides an allowance for doubtful accounts by recording a provision for uncollectible accounts based upon its historical collection experience, potential inefficiencies in its billing processes and for which collectability is determined to be unlikely. Approximately 1% of the Company’s net accounts receivable are associated with patient pay and it’s the Company’s policy to reserve 100% of the outstanding accounts receivable balances for dialysis services when those amounts due have been outstanding for more than three months and to reserve 100% of the outstanding accounts receivable balances for DMG’s services when those amounts due have been outstanding for more than twelve months.
Income taxes	The Company recognizes accrued interest and penalties related to unrecognized tax benefits in its income tax expense.
Long-term debt	On September 30, 2016, the Company’s interest rate swap agreements expired. The Company had entered into several interest rate swap agreements as a means of hedging its exposure to and volatility from variable-based interest rate changes as part of its overall interest rate risk management strategy. These agreements were not held for trading or speculative purposes and had the economic effect of converting the LIBOR variable component of the Company’s interest rate to a fixed rate. These swap agreements were designated as cash flow hedges, and as a result, hedge-effective gains or losses resulting from changes in the fair values of these swaps were reported in other comprehensive income until such time as the hedged forecasted cash flows occurred, at which time the amounts were reclassified into net income. Net amounts paid or received for each specific swap tranche that have settled have been reflected as adjustments to debt expense. In addition, the Company has entered into several active and forward interest rate cap agreements that have the economic effect of capping the Company’s maximum exposure to LIBOR variable interest rate changes on specific portions of the Company’s floating rate debt, as described below. The cap agreements are also designated as cash flow hedges and, as a result, changes in the fair values of these cap agreements are reported in other comprehensive income. The amortization of the original cap premium is recognized as a component of debt expense on a straight-line basis over the term of the cap agreements. The swap and cap agreements do not contain credit-risk contingent features.
Long-term incentive compensation	The Company’s stock-based compensation awards are measured at their estimated fair values on the date of grant if settled in shares or at their estimated fair values at the end of each reporting period if settled in cash. The value of stock-based awards so measured is recognized as compensation expense on a cumulative straight-line basis over the vesting terms of the awards, adjusted for expected forfeitures.
Comprehensive income	The reclassification of net swap and cap realized losses into income are recorded as debt expense in the corresponding consolidated statements of income. The reclassification of net investment realized gains into income are recorded in other income in the corresponding consolidated statements of income.
Variable interest entities	The Company relies on the operating activities of certain legal entities that it does not directly own or control, but over which it has indirect influence and of which it is considered the primary beneficiary. These entities are subject to the consolidation guidance applicable to variable interest entities (VIEs). Under U.S. generally accepted accounting principles (GAAP), VIEs typically include entities for which (i) the entity’s equity is not sufficient to finance its activities without additional subordinated financial support; (ii) the equity holders as a group lack the power to direct the activities that most significantly influence the entity’s economic performance, the obligation to absorb the entity’s expected losses, or the right to receive the entity’s expected returns; or (iii) the voting rights of some investors are not proportional to their obligations to absorb the entity’s losses. The analyses upon which these consolidation determinations rest are complex, involve uncertainties, and require significant judgment on various matters, some of which could be subject to different interpretations. The Company also sponsors certain deferred compensation plans whose trusts qualify as VIEs and the Company consolidates each of these plans as their primary beneficiary. The assets of these plans are recorded in short-term or long-term investments with matching offsetting liabilities recorded in accrued compensation and benefits and other long-term liabilities.
Fair value of financial instruments	The available-for-sale securities represent investments in various open-ended registered investment companies, or mutual funds, and are recorded at estimated fair value based upon quoted prices reported by each mutual fund. The interest rate cap agreements are recorded at fair value estimated from valuation models utilizing the income approach and commonly accepted valuation techniques that use inputs from closing prices for similar assets and liabilities in active markets as well as other relevant observable market inputs at quoted intervals such as current interest rates, forward yield curves, implied volatility and credit default swap pricing. The Company does not believe the ultimate amount that could be realized upon settlement of these interest rate cap agreements would be materially different from the fair value estimates currently reported. See Note 9 to the condensed consolidated financial statements for further discussion. The funds on deposit with third parties represent funds held with various third parties as required by regulation or contract and invested by those parties in various investments, which are measured at estimated fair value based primarily on quoted market prices. The estimated fair value measurements of contingent earn-out obligations are primarily based on unobservable inputs including projected EBITDA, estimated probability of achieving gross margins or quality margins of certain medical procedures and the estimated probability of earn-out payments being made using an option pricing technique and a simulation model for expected EBITDA and operating income. In addition, a probability adjusted model was used to estimate the fair value amounts of the quality margins. The estimated fair value of these contingent earn-out obligations are remeasured as of each reporting date and could fluctuate based upon any significant changes in key assumptions, such as changes in the Company credit risk adjusted rate that is used to discount obligations to present value.
New accounting standards	The Company adopted Accounting Standards Update (ASU) No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis as of January 1, 2016. The amendments in this ASU modify, simplify and expand certain aspects of consolidation guidance, principally with respect to limited partnerships, service fee arrangements and related parties. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. The Company adopted ASU No. 2015-05, Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement, which amends ASC 350-40, Intangibles-Goodwill and Other-Internal-Use Software as of January 1, 2016. The provisions of this statement were applied prospectively. This ASU provides guidance to customers about whether a cloud computing arrangement includes a software license. If an arrangement includes a software license, the accounting for the license will be consistent with licenses of other intangible assets. If the arrangement does not include a license, the arrangement will be accounted for as a service contract. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. The Company adopted ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments as of January 1, 2016. The amendments in this ASU allow an acquirer to recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. This is inclusive of the effect on earnings of changes in depreciation, amortization, or other income effects as a result of the change to provisional amounts, calculated as if the accounting had been completed at the acquisition date. The amendments in this ASU were applied prospectively. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-17, Consolidation (Topic 810): Interests Held through Related Parties That Are under Common Control. The amendments in this ASU affect consolidation of variable interest entities in certain situations involving entities under common control. The amendments in this ASU are effective for the Company beginning on January 1, 2017 and are to be applied to all periods since adoption of ASU No. 2015-02, which the Company adopted effective January 1, 2016. Early adoption is permitted. The Company does not expect that adoption of this ASU will have a material effect on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory. The amendments in this ASU allow entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs, the current guidance does not allow recognition until the asset has been sold to an outside party. The amendments in this ASU are effective for the Company beginning on January 1, 2018 and are to be applied on a modified retrospective basis. Early adoption is permitted. The Company has not yet determined the effect that adoption of this ASU will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The amendments in this ASU clarify how certain cash receipts and cash payments should be classified on the statement of cash flows. The new standard is effective for the Company beginning January 1, 2018 and should be applied retrospectively to all periods presented. Early adoption is permitted. The Company has not yet determined the effect that adoption of this ASU will have on its consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instrument – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This amendment will replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable supporting information to inform credit loss estimates. The amendments in this ASU are effective for the Company beginning January 1, 2020 and early adoption is permitted only as of January 1, 2019. The Company has not yet determined the effect that adoption of this ASU will have on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, as part of its Simplification Initiative. The changes required by this ASU involve several aspects of the accounting for share-based payment transactions, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments in this ASU are effective for the Company beginning January 1, 2017 and early adoption is permitted. The method of adoption differs for each of the topics covered by the ASU. The Company continues to evaluate the effect that the implementation of this ASU will have on its consolidated financial statements, related disclosures and the timing of implementation. In March 2016, the FASB issued ASU No. 2016-07, Investments – Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting. The amendments in this ASU eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments in this ASU are effective for the Company beginning on January 1, 2017 to be applied prospectively. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The amendments in this ASU revise the accounting related to lessee accounting. Under the new guidance, lessees will be required to recognize a lease liability and a right-of-use asset for substantially all leases with lease terms in excess of twelve months. The new lease guidance also simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. The amendments in this ASU are effective for the Company beginning on January 1, 2019 and are to be applied through a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early adoption is permitted. The Company has assembled an internal lease task force that meets regularly to discuss and evaluate the overall impact of this guidance on its consolidated financial statements and related disclosures, as well as the expected timing and method of adoption. The Company believes that the new standard will have a material impact on its consolidated balance sheet but will not have a material impact on its liquidity. The Company continues to evaluate the effect that the implementation of this ASU will have on its consolidated financial statements and related disclosures. In January 2016, the FASB issued ASU No. 2016-01, Financial Statements – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The amendments in this ASU revise accounting related to (i) the classification and measurement of investments in equity securities and (ii) the presentation of certain fair value changes for financial liabilities at fair value. The amendments in this ASU are effective for the Company beginning on January 1, 2018 and are to be applied through a cumulative effect adjustment to the statement of financial position. Early adoption is permitted under certain circumstances. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in this ASU apply to all inventory with the exception of inventory measured using the last-in, first-out or the retail inventory methods. This ASU simplifies the measurement of inventory. Under this new standard, inventory should be measured using the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. The amendments in this ASU are effective for the Company beginning January 1, 2017 and are to be applied prospectively. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. When it becomes effective, this ASU will replace most existing revenue recognition guidance in U.S. GAAP. In July 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of Effective Date. This guidance approves a one-year deferral of the effective date of ASU 2014-09. The ASU now permits the Company to adopt this standard effective January 1, 2018. Early application is permitted as of the initial effective date of January 1, 2017, but not prior to that date. In March, April and May 2016, the FASB issued ASU 2016-08, ASU 2016-10, ASU 2016-11, and ASU 2016-12, Revenue from Contracts with Customers (Topic 606), each of which amends the guidance in ASU 2014-09. The Company has assembled an internal revenue task force that meets regularly to discuss and evaluate the overall impact this guidance will have on various revenue streams in the consolidated financial statements and related disclosures, as well as the expected timing and method of adoption. The Company has not yet selected a transition method nor has it determined the effect of this ASU on its ongoing financial reporting.
Investments in debt and equity securities	The Company classifies certain debt securities as held-to-maturity and records them at amortized cost based on the Company’s intentions and strategy concerning those investments. Equity securities that have readily determinable fair values, including those of mutual funds, common stock and other debt securities, are classified as available-for-sale and recorded at fair value. The investments in mutual funds classified as available-for-sale are held within a trust to fund existing obligations associated with several of the Company’s non-qualified deferred compensation plans.
Put Obligation Fair Value Estimate of Noncontrolling Interest
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Noncontrolling interests subject to put provisions and other commitments	The Company has potential obligations to purchase the noncontrolling interests held by third parties in several of its majority-owned partnerships, non-owned legal entities, and minority-owned legal entities. These obligations are in the form of put provisions and are exercisable at the third-party owners’ discretion within specified periods as outlined in each specific put provision. If these put provisions were exercised, the Company would be required to purchase the third-party owners’ noncontrolling interests at either the appraised fair market value or a predetermined multiple of earnings or cash flow attributable to the noncontrolling interests put to the Company, which is intended to approximate fair value. The methodology the Company uses to estimate the fair values of noncontrolling interests subject to put provisions assumes the higher of either a liquidation value of net assets or an average multiple of earnings, based on historical earnings, patient mix and other performance indicators that can affect future results, as well as other factors. The estimated fair values of the noncontrolling interests subject to put provisions is a critical accounting estimate that involves significant judgments and assumptions and may not be indicative of the actual values at which the noncontrolling interests may ultimately be settled, which could vary significantly from the Company’s current estimates. The estimated fair values of noncontrolling interests subject to put provisions can fluctuate and the implicit multiple of earnings at which these noncontrolling interest obligations may be settled could vary significantly depending upon market conditions including potential purchasers’ access to the capital markets, which can impact the level of competition for dialysis and non-dialysis related businesses, the economic performance of these businesses and the restricted marketability of the third-party owners’ noncontrolling interests. The amount of noncontrolling interests subject to put provisions that employ a contractually predetermined multiple of earnings rather than fair value are immaterial.