Supplemental Balance Sheet and Income Statement Information - Accumulated Other Comp Inc (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			$ 1,982,811
Other comprehensive income (loss), net of tax	$ 6,818	$ 6,497	(10,400)	$ 15,835
Balance at the end of the period	1,413,147		1,413,147
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(11,788)	(29,325)
Other comprehensive income (loss) before reclassifications			(10,694)	15,539
Amounts reclassified from accumulated other comprehensive income (loss)			294	296
Other comprehensive income (loss), net of tax			(10,400)	15,835
Balance at the end of the period	(22,188)	(13,490)	(22,188)	(13,490)
Gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(65)	(492)
Amounts reclassified from accumulated other comprehensive income (loss)			214	212
Other comprehensive income (loss), net of tax			214	212
Balance at the end of the period	149	(280)	149	(280)
Defined benefit pension plan items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(3,778)	(3,945)
Amounts reclassified from accumulated other comprehensive income (loss)			80	84
Other comprehensive income (loss), net of tax			80	84
Balance at the end of the period	(3,698)	(3,861)	(3,698)	(3,861)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period			(7,945)	(24,888)
Other comprehensive income (loss) before reclassifications			(10,694)	15,539
Other comprehensive income (loss), net of tax			(10,694)	15,539
Balance at the end of the period	$ (18,639)	$ (9,349)	$ (18,639)	$ (9,349)