Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 24,684	$ 14,500
Adjustments to reconcile net income to net cash provided by operating activities, net of acquisitions:
Depreciation and amortization	8,872	7,365
Deferred income taxes	51	105
Stock-based compensation	3,987	4,186
Amortization of debt issuance costs under the credit facility	554	533
Provision for doubtful accounts	681	168
Loss (gain) of disposal of assets and asset impairment	1,242	(90)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	30,746	(19,957)
Prepaid expenses and other current assets	(2,592)	2,822
Accounts payable	(2,496)	1,856
Accrued expenses and other long-term liabilities	7,570	(3,404)
Net cash provided by operating activities	73,299	8,084
Cash flows from investing activities:
Purchases of property and equipment	(5,893)	(3,077)
Acquisitions of businesses, net of cash acquired	(11,869)	(53,224)
Proceeds from disposal of assets	255
Net cash used in investing activities	(17,507)	(56,301)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of offering costs		172,945
Borrowings on revolver — credit facility		23,458
Borrowings on term loan — credit facility		19,600
Payments on term loan — credit facility	(490)	(245)
Payments for debt issuance costs under the credit facility		(361)
Payments on financing lease obligations	(22)	(54)
Cash received from exercise of stock options	3,337	2,077
Net cash provided by financing activities	2,825	217,420
Net change in cash	58,617	169,203
Cash, at beginning of period	111,714	70,406
Cash, at end of period	170,331	239,609
Supplemental disclosures of cash flow information:
Cash paid for interest	1,869	1,594
Cash paid for income taxes	9,119	5,808
Supplemental disclosures of non-cash investing and financing activities:
Leasehold improvements acquired through tenant allowances	$ 4,871	$ 682