Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies [Line Items]
Net rental expense	$ 2,200,000	$ 1,700,000	$ 1,600,000
Future Obligations for Minimum Rentals Under Non-Cancelable Operating Lease Commitments
2013	1,778,000
2014	1,577,000
2015	1,418,000
2016	1,271,000
2017	964,000
Thereafter	9,118,000
Total lease commitments	$ 16,126,000
Minimum [Member]
Commitments and Contingencies [Line Items]
Lease Term, Facilities	5 years
Maximum [Member]
Commitments and Contingencies [Line Items]
Lease Term, Facilities	10 years
Lease Term, Equipment	5 years