Intangible Assets (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) item	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) item	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Intangible Assets
Weighted-Average Amortization Period			10 years
Gross Carrying Amount	$ 10,427		$ 10,427		$ 10,427
Accumulated Amortization	$ (6,368)		$ (6,368)		$ (5,838)
Number of other patterns | item	0		0
Amortization expense	$ 300	$ 300	$ 530	$ 530
Expected amortization expense for year one	1,100		1,100
Expected amortization expense for year two	1,100		1,100
Expected amortization expense for year three	1,100		1,100
Expected amortization expense for year four	$ 900		$ 900