Commitments and Contingencies - Narrative (Details) (USD $)	1 Months Ended	12 Months Ended
	Jul. 31, 2005 extension	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Sale Leaseback Transaction [Abstract]
Rent expense		$ 173,000	$ 173,000	$ 173,000
Office building
Operating Leases, Rent Expense, Net [Abstract]
Lease term of assets subject to operating leases		9 years
Vehicles
Operating Leases, Rent Expense, Net [Abstract]
Rent expense		2,900,000	2,700,000	2,800,000
Other facilities | Minimum
Operating Leases, Rent Expense, Net [Abstract]
Lease term of assets subject to operating leases		1 year
Other facilities | Maximum
Operating Leases, Rent Expense, Net [Abstract]
Lease term of assets subject to operating leases		5 years
Land
Operating Leases, Rent Expense, Net [Abstract]
Lease term of assets subject to operating leases		20 years
Prepayments of future operating lease payments		250,000
Office building
Sale Leaseback Transaction [Abstract]
Proceeds from the sale-leaseback transaction	2,100,000
Sale-leaseback term	10 years
Deferred gain on sale-leaseback transaction	562,000
Gain recognized on sale-lease back transaction		$ 56,000	$ 56,000	$ 56,000
Options to extend term of the lease for additional five years	2
Maximum extension term of each option to extend	5 years