Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 10, 2013
Commitments and Contingencies
Estimated life-cycle costs, minimum				$ 700,000
Estimated life-cycle costs, maximum				3,400,000
Commitments and Contingencies
Reserve for estimated life-cycle costs	200,000
Maximum operating lease term	10 years
Rent expense under operating leases	3,200,000	3,000,000	2,500,000
Future minimum payments under non-cancelable operating leases
2014	2,481,000
2015	1,493,000
2016	960,000
2017	550,000
2018	181,000
Thereafter	89,000
Total	5,754,000
Effective term of the employment agreements	1 year
Automatic extension term of the employment agreements	1 year
Notice period for termination of employment agreements	60 days
Automatic extension term of the employment agreements in case of change in control	2 months
Minimum
Commitments and Contingencies
Loss contingency, entity portion of potential cost	100,000
Maximum
Commitments and Contingencies
Loss contingency, entity portion of potential cost	$ 500,000
Period for occurrence of certain termination events following a change in control to provide increased severance payments	12 months