Supplemental Balance Sheet and Income Statement Information - Accumulated Other Comp Inc (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			$ 2,700,850
Adoption of ASU No. 2016-01			0
Other comprehensive income (loss), net of tax	$ 6,497	$ (5,422)	15,835	$ (23,758)
Balance at the end of the period	2,381,514		2,381,514
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(29,325)	11,185
Other comprehensive income (loss) before reclassifications			15,539	(14,913)
Amounts reclassified from accumulated other comprehensive income (loss)			296	299
Adoption of ASU No. 2016-01				(9,144)
Other comprehensive income (loss), net of tax			15,835	(23,758)
Balance at the end of the period	(13,490)	(12,573)	(13,490)	(12,573)
Gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(492)
Amounts reclassified from accumulated other comprehensive income (loss)			212
Other comprehensive income (loss), net of tax			212
Balance at the end of the period	(280)		(280)
Gains (losses) on cash flow hedges.
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period				(922)
Amounts reclassified from accumulated other comprehensive income (loss)				216
Other comprehensive income (loss), net of tax				216
Balance at the end of the period		(706)		(706)
Unrealized gains (losses) on available-for-sale securities
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period				9,144
Adoption of ASU No. 2016-01				(9,144)
Other comprehensive income (loss), net of tax				(9,144)
Defined benefit pension plan items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(3,945)	(4,111)
Amounts reclassified from accumulated other comprehensive income (loss)			84	83
Other comprehensive income (loss), net of tax			84	83
Balance at the end of the period	(3,861)	(4,028)	(3,861)	(4,028)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(24,888)	7,074
Other comprehensive income (loss) before reclassifications			15,539	(14,913)
Other comprehensive income (loss), net of tax			15,539	(14,913)
Balance at the end of the period	$ (9,349)	$ (7,839)	$ (9,349)	$ (7,839)