Derivative Financial Instruments - Narratives (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) instrument	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2012 USD ($) instrument	Jun. 24, 2012 USD ($) instrument
Derivative
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax	$ 350	$ 0
Foreign exchange derivative
Derivative
Derivative Asset	616
Derivative Liability	356
Cash Flow Hedge | Designated As Hedging | Foreign currency forward contracts
Derivative
Foreign currency cash flow hedge gain to be reclassified during next 12 months	350
Derivative, notional amount	29,500
Derivative Asset	260
Derivative Liability			$ 601	$ 0
Cash Flow Hedge | Designated As Hedging | Interest rate swap
Derivative
Derivative, notional amount					$ 25,000	$ 50,000
Number of derivative instruments held | instrument		3			4	4
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months	156
Derivative Liability	$ (650)		$ (753)	$ 768