CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net income	$ 377,778	$ 425,521	$ 410,573
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of fixed assets - net	(868)	156	946
Asset impairments	3,087	10,155	0
Depreciation and amortization	41,651	39,543	39,049
Amortization of intangible assets	41,844	37,333	38,495
Amortization of debt issuance expenses	1,716	1,355	1,332
Share-based compensation expense	19,375	27,669	24,754
Deferred income taxes	8,238	6,625	(4,345)
Non-cash interest expense associated with forward starting swaps	6,021	6,327	6,475
Changes in (net of the effect from acquisitions):
Receivables	20,873	22,338	(23,419)
Inventories	36,523	(3,322)	(23,031)
Other current assets	(10,276)	(2,361)	25,162
Trade accounts payable	2,702	(9,115)	(1,220)
Deferred revenue	38,967	8,680	(3,247)
Accrued expenses	(15,326)	(46,664)	7,125
Other - net	(3,032)	3,822	(19,304)
Net cash flows provided by operating activities	569,273	528,062	479,345
Cash flows from investing activities
Purchases of property, plant and equipment	(51,545)	(50,912)	(56,089)
Purchase of intellectual property	0	0	(4,000)
Acquisition of businesses, net of cash acquired	(123,133)	(87,180)	(20,205)
Proceeds from disposal of fixed assets	2,287	962	363
Contributions received from joint venture partner	120	0	0
Other - net	(306)	115	(1,500)
Net cash flows used in investing activities	(172,577)	(137,015)	(81,431)
Cash flows from financing activities
Borrowings under revolving credit facilities	150,000	0
Proceeds from issuance of 3.0% Senior Notes	499,100	0	0
Payment of 4.5% Senior Notes	(300,000)	0	0
Payments under revolving credit facilities	(150,000)	0	(11,284)
Payments under other long-term borrowings	(396)	(50,057)	0
Payment of make-whole redemption premium	(6,756)	0	0
Debt issuance costs	(4,749)	0	0
Dividends paid	(151,838)	(147,208)	(127,478)
Proceeds from stock option exercises	44,587	38,809	27,639
Repurchases of common stock	(110,342)	(54,668)	(173,926)
Shares surrendered for tax withholding	(12,208)	(12,596)	(11,555)
Settlement of foreign exchange contracts	0	0	6,593
Other - net	0	(1,865)	0
Net cash flows used in financing activities	(42,602)	(227,585)	(290,011)
Effect of exchange rate changes on cash and cash equivalents	39,176	2,712	(17,446)
Net increase in cash	393,270	166,174	90,457
Cash and cash equivalents at beginning of year	632,581	466,407	375,950
Cash and cash equivalents at end of year	1,025,851	632,581	466,407
Cash paid for:
Interest	35,152	36,683	36,327
Income taxes - net	87,193	109,032	90,733
Significant non-cash activities:
Contingent consideration for acquisition	0	0	3,375
Debt acquired with acquisition of business	0	51,130	0
Capital expenditures for construction of new leased facility	$ 0	$ 0	$ 11,616