CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended				9 Months Ended	12 Months Ended			24 Months Ended
	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Apr. 01, 2018	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 19,984	$ 20,849	$ 26,970	$ 30,068		$ 89,566	$ 119,832	$ 85,718
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization						62,795	55,052	33,541
Amortization of convertible notes debt discount						7,021	5,885	0
Stock-based compensation expense						15,436	13,981	10,411
Deferred income taxes						5,593	759	(6,477)
Other						(1,661)	(2,841)	422
Change in operating assets and liabilities, net of acquisitions of businesses:
Trade receivables						5,768	26,680	(11,152)
Inventories						19,682	92	(35,270)
Prepaid expenses and other assets						(12,869)	1,654	(7,600)
Accounts payable, accrued liabilities and other						1,079	(21,081)	30,308
Net cash provided by operating activities						192,410	200,013	99,901
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(27,661)	(34,486)	(22,497)
Proceeds from sale of property, equipment, facility and other						4,402	6,463	1,211
Business acquisitions, net of cash acquired						(55,953)	(343,347)	(251,851)
Net cash used in investing activities						(79,212)	(371,370)	(273,137)
CASH FLOWS FROM FINANCING ACTIVITIES
Term debt borrowings						7,500	36,981	0
Term debt repayments						(6,250)	(7,691)	(15,766)
Borrowing on revolver						653,129	1,211,464	673,830
Repayments on revolver						(910,461)	(1,106,528)	(576,860)
Proceeds from senior notes offering						300,000
Proceeds from convertible notes offering						0	172,500	0
Purchase of convertible notes hedges						0	(31,481)	0
Proceeds from sale of warrants						0	18,147	0
Cash dividends paid to shareholders						(5,798)
Stock repurchases under buyback program						(3,815)	(107,567)	0
Proceeds from public offering of common stock, net of expenses						0	0	93,306
Payments related to vesting of stock-based awards, net of shares tendered for taxes						(3,380)	(2,698)	(4,821)
Payment of deferred financing costs						(7,219)	(7,632)	(997)
Payment of contingent consideration from a business acquisition					$ (4,400)	(4,416)	0	0
Other financing activities						7	(10)	862
Net cash provided by financing activities						19,297	175,485	169,554
Increase (decrease) in cash and cash equivalents						132,495	4,128	(3,682)
Cash and cash equivalents at beginning of year		$ 6,895		$ 2,767	$ 6,895	6,895	2,767	6,449	$ 2,767
Cash and cash equivalents at end of year	$ 139,390		$ 6,895			$ 139,390	$ 6,895	$ 2,767	$ 139,390