CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 1,014,589	$ 784,147	$ 467,468
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Depreciation	91,073	80,119	70,834
Amortization	34,412	46,624	49,821
Stock-based compensation	45,643	44,906	37,897
Provision for excess and obsolete inventory	15,475	17,534	15,244
Retirement plans actuarial losses (gains)	(2,217)	10,284	8,176
Contingent consideration adjustment	(7,227)	(23,271)	(19,257)
Deferred taxes	(17,305)	(15,688)	(9,456)
(Gains) losses on investments	(6,410)	(7,898)	(6,033)
Investment impairment	0	0	15,000
Other	271	1,557	766
Changes in operating assets and liabilities, net of businesses acquired:
Accounts receivable	(57,778)	(129,451)	(70,440)
Inventories	6,495	(8,438)	(27,408)
Prepayments and other assets	(175,846)	(64,418)	(23,784)
Accounts payable and other accrued expenses	129,499	73,167	49,279
Deferred revenue and customer advances	9,873	39,974	39,313
Retirement plans contributions	(5,405)	(5,382)	(5,086)
Income taxes	(5,604)	25,169	(13,584)
Loss on convertible debt conversion	28,828	0	0
Net cash provided by operating activities	1,098,366	868,935	578,750
Cash flows from investing activities:
Purchases of property, plant and equipment	(132,472)	(184,977)	(134,642)
Purchases of marketable securities	(661,781)	(900,196)	(662,701)
Proceeds from maturities of marketable securities	660,148	479,678	611,927
Proceeds from sales of marketable securities	266,466	35,006	105,586
Proceeds from life insurance	0	546	2,912
Purchase of investment and acquisition of businesses, net of cash acquired	(12,000)	149	(79,742)
Net cash (used for) provided by investing activities	120,361	(569,794)	(156,660)
Cash flows from financing activities:
Issuance of common stock under stock purchase and stock option plans	32,686	28,527	29,312
Repurchase of common stock	(600,000)	(88,465)	(500,000)
Dividend payments	(65,977)	(66,482)	(61,305)
Payments related to net settlement of employee stock compensation awards	(32,303)	(23,014)	(14,741)
Payments of contingent consideration	0	(8,852)	(27,615)
Payments of convertible debt principal	(342,990)	0	0
Net cash (used for) provided by financing activities	(1,008,584)	(158,286)	(574,349)
Effects of exchange rate changes on cash and cash equivalents	(2,065)	(658)	(569)
Increase (decrease) in cash and cash equivalents	208,078	140,197	(152,828)
Cash and cash equivalents at beginning of year	914,121	773,924	926,752
Cash and cash equivalents at end of year	1,122,199	914,121	773,924
Cash paid for:
Interest	4,236	6,435	5,996
Income taxes	172,134	106,577	81,410
Non-cash investing activities:
Capital expenditures incurred but not yet paid:	$ 1,973	$ 3,666	$ 4,068