Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Valuation Allowance [Line Items]
Deferred Tax Assets, Gross	$ 225,000		$ 225,000
Deferred Tax Assets, Valuation Allowance	29,000		29,000
Provision for (benefit from) income taxes	6,236	$ 4,254	16,119	$ 14,878
Unrecognized tax benefits	22,900		22,900		$ 21,900
Portion of unrecognized tax benefits, which if recognized, would be recorded as an income tax benefit	2,200		2,200
Unrecognized tax benefits included in long-term income taxes payable	2,200		2,200		2,200
Unrecognized tax benefits, reduction of long-term deferred tax assets	20,700		20,700		$ 19,700
Foreign Tax Authority [Member]
Valuation Allowance [Line Items]
Income Taxes Paid	$ 4,700	$ 5,500	$ 15,600	$ 16,500