CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities
Net income	$ 69,402	$ 48,965
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization of property and equipment	30,850	28,575
Amortization of operating lease right-of-use assets	13,281	11,597
Amortization of intangibles	20,378	18,065
Amortization of deferred financing costs and debt discount	1,000	845
Provision for credit losses	3,839	3,173
Write-off of debt issuance costs		2,774
Gain on sale of property and equipment	(592)	(69)
Noncash stock compensation	8,050	6,442
Deferred income taxes	(3,405)
Amortization of terminated interest rate swap	508
Changes in assets and liabilities, excluding effects of acquisitions
Accounts receivable	(9,624)	(29,144)
Inventories	5,983	(852)
Other assets	9,027	(4,845)
Accounts payable	(14,746)	2,535
Income taxes receivable/payable	14,192	13,487
Other liabilities	(4,259)	4,969
Net cash provided by operating activities	143,884	106,517
Cash flows from investing activities
Purchases of investments	(776)	(17,352)
Maturities of short term investments	37,473	22,560
Purchases of property and equipment	(25,515)	(37,267)
Acquisitions of businesses	(38,825)	(24,740)
Proceeds from sale of property and equipment	828	563
Other	(2,662)	(1,795)
Net cash used in investing activities	(29,477)	(58,031)
Cash flows from financing activities
Proceeds from senior notes		300,000
Payments on term loan		(195,750)
Proceeds from vehicle and equipment notes payable	17,759	23,767
Debt issuance costs	(157)	(5,191)
Principal payments on long-term debt	(19,801)	(15,278)
Principal payments on finance lease obligations	(1,998)	(3,398)
Acquisition-related obligations	(3,896)	(5,797)
Repurchase of common stock	(15,759)
Surrender of common stock awards by employees	(973)	(2,331)
Net cash (used in) provided by financing activities	(24,825)	96,022
Net change in cash and cash equivalents	89,582	144,508
Cash and cash equivalents at beginning of period	177,889	90,442
Cash and cash equivalents at end of period	267,471	234,950
Supplemental disclosures of cash flow information Net cash paid during the period for:
Interest	24,130	17,746
Income taxes, net of refunds	13,798	3,790
Supplemental disclosure of noncash activities
Right-of-use assets obtained in exchange for operating lease obligations	18,340	11,593
Termination of operating lease obligations and right-of-use assets		(2,814)
Property and equipment obtained in exchange for finance lease obligations	853	2,175
Seller obligations in connection with acquisition of businesses	6,965	4,322
Unpaid purchases of property and equipment included in accounts payable	$ 1,229	$ 1,527