Long-Term Debt Obligations (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Future principal payments of long-term debt
2013	$ 300
2014	5,300
2015	300
2016	300
2017	300
Thereafter	900
Total	7,400	15,381
Interest expense
Interest expense on notes to former owners	255	795	627
Interest expense on borrowings and unused commitment fees	444	243	287
Letter of credit fees	667	622	447
Amortization of debt financing costs	229	226	338
Total	$ 1,595	$ 1,886	$ 1,699