Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments
Rental expense	$ 300,000	$ 200,000	$ 100,000
Future minimum payments for operating leases
2014	218,000
2015	65,000
2016	7,000
Total	290,000
Future minimum payments for other commitments
2014	6,481,000
2015	2,745,000
2016	1,704,000
2017	269,000
2018 and thereafter	6,000
Total	11,205,000
Future minimum payments for operating leases and other commitments
2014	6,699,000
2015	2,810,000
2016	1,711,000
2017	269,000
2018 and thereafter	6,000
Total	$ 11,495,000