CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net income	$ 54,504	$ 41,325
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization of property and equipment	21,570	20,623
Amortization of operating lease right-of-use assets	10,549	8,545
Amortization of intangibles	17,574	13,404
Amortization of deferred financing costs and debt discount	663	670
Provision for credit losses	102	2,668
Gain on sale of property and equipment	(560)	(144)
Noncash stock compensation	6,693	5,415
Deferred income taxes	0	(1,679)
Amortization of terminated interest rate swap		0
Changes in assets and liabilities, excluding effects of acquisitions
Accounts receivable	(3,953)	(3,158)
Inventories	(19,973)	6,072
Other assets	(1,225)	9,351
Accounts payable	3,724	(18,504)
Income taxes receivable/payable	(297)	16,015
Other liabilities	(7,538)	4,922
Net cash provided by operating activities	83,435	105,525
Cash flows from investing activities
Purchases of investments	0	(776)
Maturities of short term investments	0	22,050
Purchases of property and equipment	(20,278)	(16,345)
Acquisitions of businesses, net of cash acquired of $168 and $0 in 2021 and 2020, respectively	(67,715)	(12,625)
Proceeds from sale of property and equipment	1,112	314
Other	(5)	(1,340)
Net cash used in investing activities	(86,886)	(8,722)
Cash flows from financing activities
Proceeds from vehicle and equipment notes payable	15,103	12,768
Debt issuance costs	0	(157)
Principal payments on long-term debt	(13,012)	(13,205)
Principal payments on finance lease obligations	(1,041)	(1,392)
Dividends paid	(17,607)	0
Acquisition-related obligations	(2,050)	(3,486)
Surrender of common stock awards by employees	0	(15,759)
Net cash used in financing activities	(24,158)	(22,204)
Net change in cash and cash equivalents	(27,609)	74,599
Cash and cash equivalents at beginning of period	231,520	177,889
Cash and cash equivalents at end of period	203,911	252,488
Supplemental disclosures of cash flow information
Interest	12,899	13,006
Income taxes, net of refunds	15,288	476
Supplemental disclosure of noncash activities
Right-of-use assets obtained in exchange for operating lease obligations	16,967	10,229
Release of indemnification of acquisition-related debt	2,036	0
Property and equipment obtained in exchange for finance lease obligations	1,134	600
Seller obligations in connection with acquisition of businesses	12,954	4,037
Unpaid purchases of property and equipment included in accounts payable	886	1,981
Common Stock Awards
Cash flows from financing activities
Surrender of common stock awards by employees	$ (5,551)	$ (973)