CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities:
Net income	$ 28,634	$ 26,108
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	7,548	6,348
Stock-based compensation expense	3,919	3,077
Deferred income taxes	1,714	2,522
(Loss) gain on disposal of assets	(126)	154
Impairment of intangibles and other	778	0
Changes in operating assets and liabilities, net of acquisitions:
Receivables	(18,897)	(1,926)
Prepaid expenses and other assets	(6,521)	(2,329)
Prepaid income taxes	4,624	(3,296)
Accounts payable and accrued expenses	8,729	15,119
Income taxes payable	0	(3,499)
Net amounts due to/from governmental entities	(704)	498
Net cash provided by operating activities	29,698	42,776
Investing activities:
Purchases of property, building and equipment	(13,760)	(5,341)
Payments to Acquire Businesses, Net of Cash Acquired	(13,086)
Cash acquired from business combination, net of cash paid		(22,704)
Advanced payments on acquisitions	0	(523)
Net cash used in investing activities	(674)	(28,568)
Financing activities:
Proceeds from line of credit	270,084	19,000
Payments on line of credit	(278,884)	(22,000)
Proceeds from employee stock purchase plan	634	469
Payments on debt	135	(129)
Payments on deferred financing fees	(1,881)	0
Noncontrolling interest distributions	(5,763)	(5,167)
Withholding taxes paid on stock-based compensation	(4,095)	(2,744)
Purchase of additional controlling interest	(55)	(184)
Sale of noncontrolling interest	3,322	251
Net cash used in financing activities	(16,503)	(10,504)
Change in cash	12,521	3,704
Cash at beginning of period	2,849	3,264
Cash at end of period	15,370	6,968
Supplemental disclosures of cash flow information:
Interest paid	3,112	1,762
Income taxes paid	$ 2,139	$ 17,320