Goodwill and Intangible Asset (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets [Abstract]
Goodwill	$ 14,916,000		$ 14,916,000	$ 15,100,000
Goodwill allocation adjustment		142,000
Estimated useful lives customer relationship	5 years
Amortization of intangible assets	600,000	600,000
Annual amortization expense	2,300,000
Number of years intangible assets will be amortized	3 years
Asset impairment charges	0
Finite-Lived Intangible Assets [Line Items]
Cost	11,286,000		11,286,000
Accumulated Amortization	3,950,000		3,386,000
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	11,286,000		11,286,000
Accumulated Amortization	$ 3,950,000		$ 3,386,000