CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Cash Flows from Operating Activities:
Net income	$ 35,147	$ 34,040	$ 67,193	$ 65,613
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			11,672	8,074
Non-cash compensation	6,725	5,538	12,634	12,153
Non-cash 401(k) employer match			0	4,686
Amortization and impairment of operating lease right of use assets			18,558	17,495
Gain on disposal of property and equipment			(94)	(2)
Loss on sale of equity method investment			2,980	0
Write-off of other comprehensive income			(15)	0
Deferred income taxes			(4,036)	5,875
Equity in earnings from equity method investments	(487)	(3,716)	(964)	(4,932)
Amortization of deferred debt issuance costs/debt discount			437	433
Return on equity investment			2,744	842
Changes in operating assets and liabilities, net of impact of acquisitions:
Patient accounts receivable			8,997	(24,165)
Other current assets			(3,469)	(8,343)
Other assets			(675)	(56)
Accounts payable			(6,452)	(9,475)
Accrued expenses			27,990	29,262
Other long-term obligations			20,746	(181)
Operating lease liabilities			(16,365)	(16,200)
Operating lease right of use assets			(1,924)	(1,754)
Net cash provided by operating activities			139,957	79,325
Cash Flows from Investing Activities:
Proceeds from sale of deferred compensation plan assets			21	213
Proceeds from the sale of property and equipment			80	146
Purchases of property and equipment			(1,701)	(2,693)
Investments in equity method investees			(875)	(210)
Proceeds from sale of equity method investment			17,876	0
Acquisitions of businesses, net of cash acquired			(299,723)	(345,414)
Net cash used in investing activities			(284,322)	(347,958)
Cash Flows from Financing Activities:
Proceeds from issuance of stock upon exercise of stock options			2,947	1,343
Proceeds from issuance of stock to employee stock purchase plan			1,686	1,534
Shares withheld to pay taxes on non-cash compensation			(6,384)	(4,490)
Noncontrolling interest distribution			(372)	(457)
Proceeds from borrowings under term loan			0	175,000
Proceeds from borrowings under revolving line of credit			424,500	184,500
Repayments of borrowings under revolving line of credit			(259,500)	(92,000)
Principal payments of long-term obligations			(4,675)	(2,277)
Debt issuance costs			0	(847)
Provider relief fund advance			70,000	0
Net cash provided by financing activities			228,202	262,306
Net increase (decrease) in cash, cash equivalents and restricted cash			83,837	(6,327)
Cash, cash equivalents and restricted cash at beginning of period			96,490	20,229	$ 20,229
Cash, cash equivalents and restricted cash at end of period	$ 180,327	$ 13,902	180,327	13,902	$ 96,490
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest			3,292	4,187
Cash paid for income taxes, net of refunds received			8,153	7,849
Cash paid for operating lease liabilities			18,289	17,954
Cash paid for finance lease liabilities			986	792
Supplemental Disclosures of Non-Cash Activity:
Right of use assets obtained in exchange for operating lease liabilities			18,891	102,231
Right of use assets obtained in exchange for finance lease liabilities			487	1,806
Reductions to right of use assets resulting from reductions to operating lease liabilities			$ 407	$ 911