Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies
Rental payments under operating leases	$ 1,662	$ 1,814	$ 1,808
Future minimum lease payments
2014	1,449
2015	1,383
2016	1,419
2017	1,454
2018 and thereafter	3,576
Total	$ 9,281