Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss), Net [Rollforward]
Beginning balance	$ 2,091,808
Ending Balance	2,106,829
Foreign currency
Accumulated Other Comprehensive Income (Loss), Net [Rollforward]
Beginning balance	(28,128)
Other comprehensive income (loss) before reclassifications	13,088
Amounts reclassified from accumulated other comprehensive income, net of tax	0
Net other comprehensive income (loss)	13,088
Ending Balance	(15,040)
Unrealized gain (loss) in Accumulated OCI
Accumulated Other Comprehensive Income (Loss), Net [Rollforward]
Beginning balance	1,119
Other comprehensive income (loss) before reclassifications	(743)
Amounts reclassified from accumulated other comprehensive income, net of tax	594
Net other comprehensive income (loss)	(149)
Ending Balance	970
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss), Net [Rollforward]
Beginning balance	(27,009)
Other comprehensive income (loss) before reclassifications	12,345
Amounts reclassified from accumulated other comprehensive income, net of tax	594
Net other comprehensive income (loss)	12,939
Ending Balance	$ (14,070)