Derivatives and Hedging Activities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Net of tax effect on unrealized loss on derivatives	$ (500)	$ (300)
Percentage of option to prepay in equity offerings (up to)	40.00%
Period of option to prepay using proceeds from equity offering	180 days
Percentage of principal amount outstanding	50.00%
Redemption price percentage	108.25%
Other Noncurrent Liabilities
Derivative [Line Items]
Fair value of embedded derivative liability	$ 0		$ 0
Other Operating Income (Expense)
Derivative [Line Items]
Change in fair value in amount included as other income (expense)	0	13,200
Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Notional foreign exchange contract outstanding	88,000		88,000
Net of tax effect on unrealized loss on derivatives	600	300
Loss recognized in other comprehensive income (loss)	1,200	$ 500
Designated as Hedging Instrument | Foreign Exchange Contract | Other Noncurrent Liabilities
Derivative [Line Items]
Fair value asset of derivative instrument	500		$ 2,400
Designated as Hedging Instrument | Foreign Exchange Contract | Other Operating Income (Expense)
Derivative [Line Items]
Loss recognized in other comprehensive income (loss)	19
Ineffective portion of loss	$ 67
Senior Secured Notes Due 2021
Derivative [Line Items]
Percentage of option to prepay principal amount (equal to)	100.00%
Senior Notes | Senior Secured Notes Due 2021
Derivative [Line Items]
Periodic payment	$ 575,000