Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 63,401	$ 74,120		$ 68,347	$ 28,214	$ 205,410	$ 109,747
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization						80,211	73,366
Stock-based compensation expense						20,295	13,646
Other non-cash items						5,418	1,818
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net						(140,768)	(103,209)
Inventories, net						(253,031)	24,423
Prepaid expenses and other assets						(28,274)	(29,489)
Accounts payable, trade						97,071	68,379
Accrued expenses and other liabilities						25,961	53,806
Net cash flows provided by operating activities						12,293	212,487
Cash flows from investing activities:
Capital expenditures						(73,872)	(28,663)
Acquisitions of businesses, net of cash acquired						(154,544)	(94,909)
Other investing activities						11,544	3,972
Net cash flows used in investing activities						(216,872)	(119,600)
Cash flows from financing activities:
Vesting of stock-based awards, net of shares tendered for payment of taxes						(8,258)	(4,807)
Proceeds from revolving credit facility						832,493	285,827
Repayments under revolving credit facility						(912,547)	(273,130)
Repayments under term loan and other borrowings						(13,375)	(15,385)
Proceeds from issuance of convertible notes						460,000	0
Purchases of convertible note hedge contracts						(100,142)	0
Proceeds from issuance of warrants concurrent with note hedge contracts						48,484	0
Payment of debt issuance costs						(11,955)	0
Payment of dividends						(64,425)	(51,535)
Payment of contingent consideration and holdbacks related to acquisitions						(8,061)	(9)
Other financing activities						1,972	(167)
Net cash flows provided by (used in) financing activities						224,186	(59,206)
Effect of exchange rate changes on cash and cash equivalents						1,187	(853)
Net increase in cash and cash equivalents						20,794	32,828
Cash and cash equivalents at beginning of period		$ 51,821	$ 68,187		$ 35,359	51,821	35,359	$ 35,359
Cash and cash equivalents cash at end of period	$ 72,615		$ 51,821	$ 68,187		72,615	68,187	$ 51,821
Supplemental disclosure of cash flow information:
Cash paid during the period for interest						9,127	12,743
Cash paid during the period for income taxes, net of refunds						75,822	16,457
Purchase of property and equipment in accrued expenses						$ 4,036	$ 2,588