Condensed consolidated interim financial statements Condensed consolidaed interim financial statements (Policies)	6 Months Ended
Jun. 30, 2024
Accounting Policies [Abstract]
Condensed consolidated interim financial statements	Condensed consolidated interim financial statements The unaudited condensed consolidated interim financial statements included in this report are prepared by the Company. In the opinion of management, all adjustments necessary for a fair presentation of the results of operations are reflected in these condensed 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 revenues, expenses, assets, liabilities, contingencies, and noncontrolling interests subject to put provisions. The most significant estimates and assumptions underlying these financial statements and accompanying notes generally involve revenue recognition and accounts receivable, certain fair value estimates, accounting for income taxes, and loss contingencies. The results of operations reflected in these interim financial statements may not necessarily be indicative of annual operating results. These 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, 2023 (2023 10-K). Prior period classifications conform to the current period presentation.
Revenue	There are significant uncertainties associated with estimating revenue, many of which take several years to resolve. These estimates are subject to ongoing insurance coverage changes, geographic coverage differences, differing interpretations of contract coverage and other payor issues, as well as patient issues, including determination of applicable primary and secondary coverage, changes in patient insurance coverage and coordination of benefits. As these estimates are refined over time, both positive and negative adjustments to revenue are recognized in the current period. Dialysis patient service revenues. Revenues are recognized based on the Company’s estimate of the transaction price the Company expects to collect as a result of satisfying its performance obligations. Dialysis patient service revenues are recognized in the period services are provided based on these estimates. Revenues consist primarily of payments from government and commercial health plans for dialysis services provided to patients. Other revenues. Other revenues consist of revenues earned by the Company's non-dialysis ancillary services as well as fees for management and administrative services to outpatient dialysis businesses that the Company does not consolidate. Other revenues are estimated and recognized in the period the performance obligation is met, subject to applicable measurement constraints. The Company's integrated kidney care (IKC) revenues include revenues earned under risk-based arrangements, including value-based care (VBC) arrangements. Under its VBC arrangements, the Company assumes full or shared financial risk for the total medical cost of care for patients below or above a benchmark. The benchmarks against which the Company incurs profit or loss on these contracts are typically based on the underlying premiums paid to the insuring entity (the Company's counterparty), with adjustments where applicable, or on trended or adjusted medical cost targets. For its IKC business, the Company recognized revenues for performance obligations satisfied in previous years of $31,309 and $23,303 during the six months ended June 30, 2024 and 2023, respectively. The delay in recognition of these amounts resulted predominantly from measurement limitations and recognition constraints on the Company's VBC contracts with health plans, many of which are complex and relatively new arrangements. The Company's revenue recognition for its government Comprehensive Kidney Care Contracting (CKCC) program also remains constrained for plan year 2023. Measurements of revenue for the Company's IKC risk-based arrangements are complex, sensitive to a number of key inputs, and require meaningful estimates for a number of factors, including but not limited to member alignment data, third-party medical claims expense, outcomes on various quality metrics, and ultimate risk adjustment factor (RAF) scores. Information and other measurement limitations on these factors may constrain revenue recognition for a risk-based arrangement until a period after the Company's performance obligations have been met.
Earnings Per Share	Basic earnings per share is calculated by dividing net income attributable to the Company by the weighted average number of common shares outstanding. Weighted average common shares outstanding include restricted stock unit awards that are no longer subject to forfeiture because the recipients have satisfied either the explicit vesting terms or retirement eligibility requirements. Diluted earnings per share includes the dilutive effect of outstanding stock-settled stock appreciation rights and unvested stock units as computed under the treasury stock method.
Short-term and Long-term Investments	Debt securities. The Company's short-term debt investments are principally bank certificates of deposit with contractual maturities longer than three months but shorter than one year. The Company's long-term debt investments are bank time deposits with contractual maturities longer than one year. These debt securities are accounted for as held-to-maturity and recorded at amortized cost, which approximated their fair values at June 30, 2024 and December 31, 2023. Equity securities. Substantially all of the Company's short-term and long-term equity investments are held within a trust to fund existing obligations associated with the Company’s non-qualified deferred compensation plans.
Long-term debt	These cap agreements are designated as cash flow hedges and, as a result, changes in their fair values are reported in other comprehensive income. The original premiums paid for the caps are amortized to debt expense on a straight-line basis over the term of each cap agreement starting from its effective date. These cap agreements do not contain credit risk-contingent features. In the second quarter of 2024 the Company entered into several forward interest rate cap agreements, described below, that have the economic effect of capping the Company's exposure to SOFR variable interest rate changes on specific portions of the Company's floating rate debt (2024 cap agreements). These 2024 cap agreements are designated as cash flow hedges and, as a result, changes in their fair values will be reported in other comprehensive income. These 2024 cap agreements do not contain credit-risk contingent features and become effective and expire as described in the table below.
Fair Value of Financial Instruments	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 7 for further discussion. As of June 30, 2024, the Company had contingent earn-out obligations associated with business acquisitions that could result in the Company paying the former owners a total of up to approximately $53,279 if certain performance targets or quality margins are met over the next one year to four years. The estimated fair value measurements of these contingent earn-out obligations are primarily based on unobservable inputs, including key financial metrics such as projected earnings before interest, taxes, depreciation, and amortization (EBITDA), revenue and other key performance indicators. The estimated fair values 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's credit risk adjusted rate that is used to discount obligations to present value.
New Accounting Standards	New accounting standards New standards not yet adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (ASU 2023-07), which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. The guidance also requires disclosure of the chief operating decision maker's (CODM) position for each segment and detail of how the CODM uses financial reporting to assess their segment’s performance. ASU 2023-07 is effective for all public entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company has completed its initial assessment of the impact of this new guidance and does not expect it to have a material impact on the Company's consolidated financial statements. In December 2023, the Financial Accounting Standards Board issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which expands income tax disclosure requirements to include additional information related to the rate reconciliation of effective tax rates to statutory rates, as well as additional disaggregation of taxes paid in both U.S. and foreign jurisdictions. The amendments in the ASU also remove disclosures related to certain unrecognized tax benefits and deferred taxes. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. The amendments may be applied prospectively or retrospectively, and early adoption is permitted. The Company is currently assessing the effect this guidance may have on its consolidated financial statement disclosures.

Condensed consolidated interim financial statements Condensed consolidaed interim financial statements (Policies)

6 Months Ended

Jun. 30, 2024

Condensed consolidated interim financial statements

The unaudited condensed consolidated interim financial statements included in this report are prepared by the Company. In the opinion of management, all adjustments necessary for a fair presentation of the results of operations are reflected in these condensed 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 revenues, expenses, assets, liabilities, contingencies, and noncontrolling interests subject to put provisions. The most significant estimates and assumptions underlying these financial statements and accompanying notes generally involve revenue recognition and accounts receivable, certain fair value estimates, accounting for income taxes, and loss contingencies. The results of operations reflected in these interim financial statements may not necessarily be indicative of annual operating results. These 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, 2023 (2023 10-K). Prior period classifications conform to the current period presentation.

Revenue

There are significant uncertainties associated with estimating revenue, many of which take several years to resolve. These estimates are subject to ongoing insurance coverage changes, geographic coverage differences, differing interpretations of contract coverage and other payor issues, as well as patient issues, including determination of applicable primary and secondary coverage, changes in patient insurance coverage and coordination of benefits. As these estimates are refined over time, both positive and negative adjustments to revenue are recognized in the current period.

Dialysis patient service revenues. Revenues are recognized based on the Company’s estimate of the transaction price the Company expects to collect as a result of satisfying its performance obligations. Dialysis patient service revenues are recognized in the period services are provided based on these estimates. Revenues consist primarily of payments from government and commercial health plans for dialysis services provided to patients.

Other revenues. Other revenues consist of revenues earned by the Company's non-dialysis ancillary services as well as fees for management and administrative services to outpatient dialysis businesses that the Company does not consolidate. Other revenues are estimated and recognized in the period the performance obligation is met, subject to applicable measurement constraints. The Company's integrated kidney care (IKC) revenues include revenues earned under risk-based arrangements, including value-based care (VBC) arrangements. Under its VBC arrangements, the Company assumes full or shared financial risk for the total medical cost of care for patients below or above a benchmark. The benchmarks against which the Company incurs profit or loss on these contracts are typically based on the underlying premiums paid to the insuring entity (the Company's counterparty), with adjustments where applicable, or on trended or adjusted medical cost targets.

For its IKC business, the Company recognized revenues for performance obligations satisfied in previous years of $31,309 and $23,303 during the six months ended June 30, 2024 and 2023, respectively. The delay in recognition of these amounts resulted predominantly from measurement limitations and recognition constraints on the Company's VBC contracts with health plans, many of which are complex and relatively new arrangements. The Company's revenue recognition for its government Comprehensive Kidney Care Contracting (CKCC) program also remains constrained for plan year 2023.

Measurements of revenue for the Company's IKC risk-based arrangements are complex, sensitive to a number of key inputs, and require meaningful estimates for a number of factors, including but not limited to member alignment data, third-party medical claims expense, outcomes on various quality metrics, and ultimate risk adjustment factor (RAF) scores. Information and other measurement limitations on these factors may constrain revenue recognition for a risk-based arrangement until a period after the Company's performance obligations have been met.

Earnings Per Share

Basic earnings per share is calculated by dividing net income attributable to the Company by the weighted average number of common shares outstanding. Weighted average common shares outstanding include restricted stock unit awards that are no longer subject to forfeiture because the recipients have satisfied either the explicit vesting terms or retirement eligibility requirements.

Diluted earnings per share includes the dilutive effect of outstanding stock-settled stock appreciation rights and unvested stock units as computed under the treasury stock method.

Short-term and Long-term Investments

Debt securities. The Company's short-term debt investments are principally bank certificates of deposit with contractual maturities longer than three months but shorter than one year. The Company's long-term debt investments are bank time deposits with contractual maturities longer than one year. These debt securities are accounted for as held-to-maturity and recorded at amortized cost, which approximated their fair values at June 30, 2024 and December 31, 2023.

Equity securities. Substantially all of the Company's short-term and long-term equity investments are held within a trust to fund existing obligations associated with the Company’s non-qualified deferred compensation plans.

Long-term debt

These cap agreements are designated as cash flow hedges and, as a result, changes in their fair values are reported in other comprehensive income. The original premiums paid for the caps are amortized to debt expense on a straight-line basis over the term of each cap agreement starting from its effective date. These cap agreements do not contain credit risk-contingent features.

In the second quarter of 2024 the Company entered into several forward interest rate cap agreements, described below, that have the economic effect of capping the Company's exposure to SOFR variable interest rate changes on specific portions of the Company's floating rate debt (2024 cap agreements). These 2024 cap agreements are designated as cash flow hedges and, as a result, changes in their fair values will be reported in other comprehensive income. These 2024 cap agreements do not contain credit-risk contingent features and become effective and expire as described in the table below.

Fair Value of Financial Instruments

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 7 for further discussion.

As of June 30, 2024, the Company had contingent earn-out obligations associated with business acquisitions that could result in the Company paying the former owners a total of up to approximately $53,279 if certain performance targets or quality margins are met over the next one year to four years. The estimated fair value measurements of these contingent earn-out obligations are primarily based on unobservable inputs, including key financial metrics such as projected earnings before interest, taxes, depreciation, and amortization (EBITDA), revenue and other key performance indicators. The estimated fair values 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's credit risk adjusted rate that is used to discount obligations to present value.

New Accounting Standards

New accounting standards

New standards not yet adopted

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (ASU 2023-07), which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. The guidance also requires disclosure of the chief operating decision maker's (CODM) position for each segment and detail of how the CODM uses financial reporting to assess their segment’s performance. ASU 2023-07 is effective for all public entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company has completed its initial assessment of the impact of this new guidance and does not expect it to have a material impact on the Company's consolidated financial statements.

In December 2023, the Financial Accounting Standards Board issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which expands income tax disclosure requirements to include additional information related to the rate reconciliation of effective tax rates to statutory rates, as well as additional disaggregation of taxes paid in both U.S. and foreign jurisdictions. The amendments in the ASU also remove disclosures related to certain unrecognized tax benefits and deferred taxes. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. The amendments may be applied prospectively or retrospectively, and early adoption is permitted. The Company is currently assessing the effect this guidance may have on its consolidated financial statement disclosures.