Supplemental Balance Sheet and Income Statement Information - Accumulated Other Comp Inc (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ 2,911,816
Other comprehensive income (loss), net of tax	(40,510)	$ 23,304	$ 35,474
Balance at the end of the period	2,700,850	2,911,816
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	11,185	(12,119)
Other comprehensive income (loss) before reclassifications	(31,962)	21,836
Amounts reclassified from accumulated other comprehensive income (loss)	596	1,468
Adoption of ASU No. 2016-01	9,144
Other comprehensive income (loss), net of tax	(40,510)	23,304
Balance at the end of the period	(29,325)	11,185	(12,119)
Gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(922)	(1,296)
Amounts reclassified from accumulated other comprehensive income (loss)	430	374
Other comprehensive income (loss), net of tax	430	374
Balance at the end of the period	(492)	(922)	(1,296)
Unrealized gains (losses) on available-for-sale securities
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	9,144	14,235
Other comprehensive income (loss) before reclassifications		(6,061)
Amounts reclassified from accumulated other comprehensive income (loss)		970
Adoption of ASU No. 2016-01	9,144
Other comprehensive income (loss), net of tax	(9,144)	(5,091)
Balance at the end of the period		9,144	14,235
Defined benefit pension plan items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(4,111)	(3,760)
Other comprehensive income (loss) before reclassifications		(475)
Amounts reclassified from accumulated other comprehensive income (loss)	166	124
Other comprehensive income (loss), net of tax	166	(351)
Balance at the end of the period	(3,945)	(4,111)	(3,760)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	7,074	(21,298)
Other comprehensive income (loss) before reclassifications	(31,962)	28,372
Other comprehensive income (loss), net of tax	(31,962)	28,372
Balance at the end of the period	$ (24,888)	$ 7,074	$ (21,298)