Supplemental Balance Sheet and Income Statement Information - Accumulated Other Comp Inc (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 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	$ 3,558	$ (3,077)	(6,842)	$ 12,758
Balance at the end of the period	1,255,648		1,255,648
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			(7,029)	12,314
Amounts reclassified from accumulated other comprehensive income (loss)			187	444
Other comprehensive income (loss), net of tax			(6,842)	12,758
Balance at the end of the period	(18,630)	(16,567)	(18,630)	(16,567)
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)			67	319
Other comprehensive income (loss), net of tax			67	319
Balance at the end of the period	2	(173)	2	(173)
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)			120	125
Other comprehensive income (loss), net of tax			120	125
Balance at the end of the period	(3,658)	(3,820)	(3,658)	(3,820)
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			(7,029)	12,314
Other comprehensive income (loss), net of tax			(7,029)	12,314
Balance at the end of the period	$ (14,974)	$ (12,574)	$ (14,974)	$ (12,574)