Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 45,126	$ 33,133	$ 25,237
Adjustments to reconcile net income to net cash provided by operating activities, net of acquisitions:
Depreciation and amortization	14,494	12,051	10,574
Deferred income taxes	7,282	(4,652)	(1,063)
Stock-based compensation	9,434	6,005	5,766
Amortization of debt issuance costs under the credit facility	804	737	716
Provision for doubtful accounts	962	918	343
Loss on sale and/or impairment of assets		1,256
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(3,916)	23,860	(37,478)
Prepaid expenses and other current assets	(8,599)	(1,973)	(792)
Government stimulus advances	(27,914)	19,393
Accounts payable	(4,810)	2,159	4,638
Accrued payroll	7,888	5,228	8,138
Accrued expenses and other liabilities	(1,263)	11,296	(4,060)
Net cash provided by operating activities	39,488	109,411	12,019
Cash flows from investing activities:
Acquisitions of businesses, net of cash acquired	(37,370)	(207,660)	(184,076)
Proceeds on disposal of businesses		255
Purchases of property and equipment	(4,645)	(6,831)	(4,621)
Net cash used in investing activities	(42,015)	(214,236)	(188,697)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs			172,945
Borrowings on revolver — credit facility	46,395	135,000	23,458
Borrowings on term loan — credit facility			19,600
Payments on term loan — credit facility	(18,130)	(735)	(735)
Payments on financing lease obligations		(22)	(63)
Payments for debt issuance costs under the credit facility	(3,029)		(372)
Cash received from exercise of stock options	1,108	3,946	3,153
Net cash provided by financing activities	26,344	138,189	217,986
Net change in cash	23,817	33,364	41,308
Cash, at beginning of period	145,078	111,714	70,406
Cash, at end of period	168,895	145,078	111,714
Supplemental disclosures of cash flow information:
Cash paid for interest	5,094	2,365	2,320
Cash paid for income taxes	17,820	10,590	7,303
Supplemental disclosures of non-cash investing and financing activities
Leasehold improvements acquired through tenant allowances		5,161	682
Tax benefit related to the amortization of tax goodwill in excess of book basis	$ 61	$ 225	$ 117