Derivative Financial Instruments - Fair Value of Derivative Instruments (Details) - Cash Flow Hedge - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest rate swap | Other Current Assets [Member]
Derivative Liability
Derivative Asset	$ 156	$ 2
Interest rate swap | Other Noncurrent Assets [Member]
Derivative Liability
Derivative Asset	494	751
Foreign currency hedges | Other Current Liabilities [Member]
Derivative Liability
Derivative Liability	0	601
Foreign currency hedges | Other Current Assets [Member]
Derivative Liability
Derivative Asset	260
Designated as Hedging Instrument [Member] | Interest rate swap
Derivative Liability
Derivative Liability	(650)	(753)	$ 768
Designated as Hedging Instrument [Member] | Foreign currency hedges
Derivatives, Fair Value [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	350
Derivative Liability
Derivative Liability		$ 601	$ 0
Derivative Asset	$ 260