Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 Lawsuit	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies [Abstract]
Rental expense	$ 8,281,000	$ 8,110,000	$ 7,621,000
Commitments under long-term non-cancelable operating leases [Abstract]
2014	3,138,000
2015	1,931,000
2016	1,910,000
2017	1,690,000
2018	804,000
Thereafter	40,000
Estimated expenses and related liabilities for losses incurred not reported to insurance carrier	1,796,000	1,545,000
Accrued medical claims	1,129,000	506,000
Minimum annual individual medical claims for stop loss coverage	100,000
Umbrella insurance coverage	2,000,000
Minimum aggregate medical claims for umbrella insurance coverage for 2013	4,500,000
Minimum aggregate medical claims for umbrella insurance coverage for 2014	4,500,000
Number of suits alleging oil and gas production	1
Total number of lawsuits	4
Accrued future legal costs	$ 200,000