CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows from Operating Activities:
Net income	$ 27,320	$ 15,199
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,593	4,417
Non-cash compensation	4,044	3,874
401(k) employer match	2,567	2,227
Loss (gain) on disposal of property and equipment	563	(16)
Deferred income taxes	2,945	9,445
Equity in (earnings) loss from equity method investments	(1,860)	106
Amortization of deferred debt issuance costs	178	185
Return on equity investment	625	150
Changes in operating assets and liabilities, net of impact of acquisitions:
Patient accounts receivable	8,260	(6,152)
Other current assets	(6,982)	(3,403)
Other assets	46	(990)
Accounts payable	(1,523)	93
Accrued expenses	(1,807)	1,386
Other long-term obligations	2,348	576
Net cash provided by operating activities	40,317	27,097
Cash Flows from Investing Activities:
Proceeds from sale of deferred compensation plan assets	462	565
Proceeds from the sale of property and equipment	5	0
Purchase of investment	0	(256)
Purchases of property and equipment	(1,462)	(4,385)
Acquisitions of businesses, net of cash acquired	(2,250)	(4,099)
Net cash used in investing activities	(3,245)	(8,175)
Cash Flows from Financing Activities:
Proceeds from issuance of stock upon exercise of stock options and warrants	125	653
Proceeds from issuance of stock to employee stock purchase plan	597	612
Shares withheld upon stock vesting	(1,305)	(758)
Non-controlling interest distribution	(28)	(42)
Principal payments of long-term obligations	(2,819)	(1,250)
Net cash used in financing activities	(3,430)	(785)
Net increase in cash and cash equivalents	33,642	18,137
Cash and cash equivalents at beginning of period	86,363	30,197
Cash and cash equivalents at end of period	120,005	48,334
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	1,065	706
Cash paid for income taxes, net of refunds received	$ 2,813	$ 284