Commitments and Contingencies (Details Textual) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]      
Rental expense for all leases, net of sublease revenues $ 4.2 $ 3.5 $ 3.2