Summary of Significant Accounting Policies (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) performance_obligation reporting_unit segment	Dec. 31, 2018 USD ($) clinic	Dec. 31, 2017 USD ($)	Oct. 01, 2019 USD ($)	Jan. 01, 2019 USD ($)
Segment Information
Number of reportable segments | segment									1
Accounts Receivable
Number of remaining performance obligations | performance_obligation									1
Payment received under government’s bundled payment system	80.00%								80.00%
Revenue related to adjustments arising from a change in the transaction price										$ 5,521,000
Medicare recovery claims, other than standard	$ 17,509,000				$ 15,820,000				$ 17,509,000	15,820,000
Medicare recovery claims	9,284,000				10,622,000				$ 9,284,000	10,622,000
Identified Non‑Amortizable Intangible Assets and Goodwill
Number of reporting units | reporting_unit									1
Goodwill	538,609,000				571,339,000				$ 538,609,000	571,339,000	$ 573,145,000	$ 576,082,000
Goodwill impaired									0	0
Impairment of Long Lived Assets
Impairment of intangible assets, indefinite-lived (excluding goodwill)									0	0
Impairment of long-lived assets									0	0
Current assets held for sale	50,099,000				577,000				50,099,000	577,000
Current liabilities held for sale	5,767,000				0				5,767,000	0
Patient service operating revenues	206,079,000	$ 211,429,000	$ 213,252,000	$ 191,762,000	207,806,000	$ 205,719,000	$ 205,952,000	$ 186,299,000	822,522,000	805,776,000
Gain on business interruption insurance									0	375,000	0
Professional fees									0	856,000	$ 717,000
Operating lease right-of-use assets	133,899,000								133,899,000
Total operating lease liabilities	145,853,000								$ 145,853,000
Minimum
Amortizable Intangible Assets
Amortizable period									5 years
Maximum
Amortizable Intangible Assets
Amortizable period									10 years
Buildings
Property and Equipment
Useful life									39 years
Equipment and information systems | Minimum
Property and Equipment
Useful life									3 years
Equipment and information systems | Maximum
Property and Equipment
Useful life									10 years
Included in prepaids and other assets
Accounts Receivable
Medicare recovery claims	9,284,000				10,622,000				$ 9,284,000	10,622,000
Interest rate derivative agreements (included in Other long-term assets)
Accounts Receivable
Medicare recovery claims	8,225,000				5,198,000				$ 8,225,000	$ 5,198,000
Accounting Standards Update 2016-02
Impairment of Long Lived Assets
Operating lease right-of-use assets													$ 138,000,000
Total operating lease liabilities													$ 149,000,000
FLORIDA
Impairment of Long Lived Assets
Number of clinics | clinic										44
TEXAS
Impairment of Long Lived Assets
Number of clinics | clinic										26
Customer Concentration Risk | Medicare And Medicaid Programs | Accounts Receivable
Accounts Receivable
Patient accounts receivable from Medicare and Medicaid programs									64.60%	70.40%
Disposal Group, Held-for-sale, Not Discontinued Operations | Certain Clinics In Pennsylvania, Ohio, and New Jersey
Impairment of Long Lived Assets
Patient service operating revenues									$ 28,621,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Certain Clinics In Maryland
Impairment of Long Lived Assets
Impairment of assets to be disposed of										$ 0
Current assets held for sale					577,000					577,000
Current liabilities held for sale					$ 0					$ 0
Disposal Group, Held-for-sale, Not Discontinued Operations | Certain Clinics in Pennsylvania, Ohio, and New Jersey and Other Property and Equipment
Identified Non‑Amortizable Intangible Assets and Goodwill
Goodwill impaired									3,289,000
Impairment of Long Lived Assets
Impairment of assets to be disposed of									1,881,000
Current assets held for sale	50,099,000								50,099,000
Asset Impairment Charges									5,170,000
Current liabilities held for sale	5,767,000								5,767,000
Operating lease right-of-use assets	$ 5,408,000								$ 5,408,000