CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 215,525	$ 279,881	$ 176,186
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	54,505	43,774	42,661
Depreciation of property, plant, and equipment	16,347	16,616	22,139
Loss (gain) on disposal of property, plant, and equipment	19	33	1,817
Amortization of intangible assets	3,274	3,667	4,364
Intangible asset impairment charges	0	0	19,571
Non-cash, loss from catastrophes	46,372	0	0
Excess and obsolete inventory charges	3,084	2,573	9,908
Operating lease asset impairment charges	0	0	3,427
Amortization of discounts or premiums on investments	4,968	4,887	1,274
Realized (gain) loss on sale of investments	182	(236)	(4,119)
Revaluation of contingent consideration	0	0	(114)
Change in deferred income taxes	(27,338)	(3,118)	(3,353)
Accounts receivable	3,454	(4,503)	(21,285)
Unbilled revenue	1,806	1,637	(848)
Inventories	(48,934)	(54,920)	(10,319)
Prepaid expenses and other current assets	(6,998)	(32,342)	(9,909)
Accounts payable	(17,277)	27,828	(1,688)
Accrued expenses	2,056	16,861	24,542
Accrued income taxes	(444)	(6,401)	(22,973)
Deferred revenue and customer deposits	4,886	14,417	6,571
Other	(12,081)	3,411	4,548
Net cash provided by operating activities	243,406	314,065	242,400
Cash flows from investing activities:
Purchases of investments	(233,720)	(668,053)	(922,867)
Maturities and sales of investments	253,983	430,969	1,104,605
Purchases of property, plant, and equipment	(19,667)	(15,455)	(13,303)
Net payments related to business acquisitions	(5,050)	0	1,004
Net cash provided by (used in) investing activities	(4,454)	(252,539)	169,439
Cash flows from financing activities:
Net payments from issuance of common stock under stock plans	9,861	63,292	125,715
Repurchase of common stock	(204,314)	(161,652)	(51,036)
Payment of dividends	(45,921)	(43,263)	(390,508)
Payment of contingent consideration	0	0	1,039
Net cash used in financing activities	(240,374)	(141,623)	(316,868)
Effect of foreign exchange rate changes on cash and cash equivalents	(3,365)	(2,815)	2,671
Net change in cash and cash equivalents	(4,787)	(82,912)	97,642
Cash and cash equivalents at beginning of year	186,161	269,073	171,431
Cash and cash equivalents at end of year	$ 181,374	$ 186,161	$ 269,073