Intangible Assets (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 item	Mar. 31, 2014	Dec. 31, 2014
Intangible Assets
Weighted-Average Amortization Period	10 years
Gross Carrying Amount	$ 10,427,000		$ 10,427,000
Accumulated Amortization	(6,103,000)		(5,838,000)
Number of other patterns	0
Amortization expense	265,000	265,000
Expected amortization expense for year one	1,100,000
Expected amortization expense for year two	1,100,000
Expected amortization expense for year three	1,100,000
Expected amortization expense for year four	1,100,000
2019	$ 300,000