Intangible Assets, Net - Net Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 30,756	$ 30,756
Accumulated Amortization	(22,839)	(19,953)
Net Balance	7,917	10,803
Impairment of intangible assets	$ 0	0	$ 0
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	6 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002	25,002
Accumulated Amortization	(17,085)	(14,585)
Net Balance	$ 7,917	10,417
Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	6 years
Gross Carrying Amount	$ 5,754	5,754
Accumulated Amortization	(5,754)	(5,368)
Net Balance	$ 0	$ 386