Income Taxes - Tax Reform and Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Estimated net tax benefit resulting from the re-measurement of the net deferred tax liability		$ 130,700
Additional net tax benefit recorded for the finalization of the provisional amounts	$ 1,100
Charge related to U.S. federal income tax on the deemed repatriation of undistributed foreign earnings		2,000
Additional charge on the deemed repatriation of undistributed foreign earnings for the finalization of the provisional amounts	200
Amount of estimated withholding tax on foreign earnings if they were distributed as dividends	3,900
Reconciliation of the change in unrecognized tax benefits
Balance at the beginning of the period	4,645	4,690	$ 4,249
Increases for tax positions related to the current year	903	200	546
Increases for tax positions related to prior years	1,438	86	627
Decreases for tax positions related to prior years	(970)	(331)	(84)
Settlements with taxing authorities	0	0	(525)
Decreases related to lapses of applicable statutes of limitation	(144)	0	(123)
Balance at the end of the period	5,872	4,645	4,690
Unrecognized tax benefits that would impact effective tax rate	3,700	2,200
Amount of income tax (benefit) expense related to interest and penalties	100	(600)	$ 900
Amount of interest and penalties accrued for	$ 700	$ 600