Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 lease	Dec. 31, 2012	Dec. 31, 2011
Lease Commitments
Number of operating leases	2
Lease expense	$ 2,700,000	$ 2,300,000	$ 1,700,000
Minimum Rental Payments
2014	2,382,000
2015	2,397,000
2016	2,552,000
2017	2,522,000
2018	2,522,000
Beyond 2018	3,572,000
Total	15,947,000
Corporate headquarters
Lease Commitments
Irrevocable standby letter of credit provided to landlord	785,000
Corporate headquarters | Low end of range
Lease Commitments
Aggregate annual cash payments	2,400,000
Corporate headquarters | High end of range
Lease Commitments
Aggregate annual cash payments	2,500,000
Off-site back-up facility | Low end of range
Lease Commitments
Aggregate annual cash payments	28,000
Off-site back-up facility | High end of range
Lease Commitments
Aggregate annual cash payments	$ 30,000