Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income	$ 294,969	$ 254,860	$ 240,755
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	83,430	74,975	65,116
Amortization	53,092	66,428	62,152
Share-based compensation expense	22,920	19,629	17,112
Provision for deferred income taxes	(7,250)	(14,008)	(11,876)
Charge for excess and obsolete inventory	15,387	11,433	4,496
Amortization of debt issuance costs	2,191	2,330	1,834
Loss on extinguishment of debt	2,378	0	2,429
Other	(1,101)	9,788	9,948
Changes in operating assets and liabilities, net of effects of acquisitions:
Trade accounts receivable and notes receivable	(27,461)	(3,164)	(17,473)
Inventories	(50,772)	(21,354)	(38,100)
Accounts payable and other accrued liabilities	40,162	(22,647)	19,950
Other current assets	(11,952)	7,784	(13,677)
Income taxes payable, refundable income taxes and noncurrent taxes payable	28,490	(3,494)	(30,381)
Other	2,191	(262)	291
Net cash provided by operating activities	446,674	382,298	312,576
Investing activities:
Acquisition of property and equipment	(131,752)	(112,355)	(110,153)
Acquisition of business, net of cash acquired	(111,912)	(277,369)	(380,694)
Other	338	3,884	4,903
Net cash used in investing activities	(243,326)	(385,840)	(485,944)
Financing activities:
Proceeds from short-term borrowings	217,000	0	0
Payments of short-term borrowings	(217,000)	0	0
Proceeds from long-term debt	400,000	0	402,000
Payments of long-term debt	(251,000)	(4,000)	(135,850)
Payments for debt issuance costs	(3,964)	0	(7,400)
Payments for dividends	(43,245)	(40,566)	(39,591)
Issuance of common stock from employee stock plans	8,738	7,291	5,577
Taxes paid related to net share settlement of equity awards	(24,800)	(8,722)	(14,686)
Repurchase and retirement of common stock	(44,563)	(80,321)	(173,781)
Deferred acquisition payment	(16,125)	0	0
Other	(2,892)	(502)	(1,858)
Net cash provided by (used in) financing activities	22,149	(126,820)	34,411
Effect of exchange rate changes on cash and cash equivalents	3,485	211	(4,389)
Increase (decrease) in cash and cash equivalents	228,982	(130,151)	(143,346)
Cash and cash equivalents at beginning of year	351,911	482,062	625,408
Cash and cash equivalents at end of year	580,893	351,911	482,062
Supplemental Cash Flow Information
Contingent consideration obligation	0	686	0
Deferred acquisition payments, net	1,482	19,848	0
Equipment purchases in accounts payable	11,921	11,285	17,624
Repurchase and retirement of common stock to be settled	0	0	5,534
Changes in dividends payable	245	349	131
Schedule of interest and income taxes paid:
Interest paid	42,575	41,711	26,248
Income taxes, net of refunds received	$ 37,228	$ 77,970	$ 54,415