Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets
Implicit discounts and adjustments	$ 15,794	$ 13,345
Compensation and benefit-related accruals	58,176	57,669
Professional malpractice liability insurance	21,447	21,885
Federal and state net operating loss and state tax credit carryforwards	28,766	32,940
Interest limitation carryforward	17,683	13,554
Stock awards	7,150	5,608
Equity investments	4,724	5,073
Operating lease liabilities	254,972	251,058
Research and experimental expenditures	21,049	9,022
Other	2,995	2,380
Deferred tax assets	432,756	412,534
Valuation allowance	(17,427)	(20,444)
Deferred tax assets, net of valuation allowance	415,329	392,090
Deferred tax liabilities
Investment in unconsolidated affiliates	(16,788)	(16,370)
Depreciation and amortization	(264,715)	(260,237)
Deferred financing costs	(1,483)	(2,425)
Operating lease right-of-use assets	(236,243)	(233,188)
Derivatives	(14,151)	(28,739)
Other	(4,167)	(3,936)
Deferred tax liabilities	(537,547)	(544,895)
Deferred tax liabilities, net of deferred tax assets	$ (122,218)	$ (152,805)