Long Term Obligations (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2011	Aug. 31, 2010
Debt Instrument [Line Items]
Base Rate And Adjusted Rate Description	The base rate for the senior term notes is a rate per annum equal to the greatest of Wells Fargo Bank, N.A. ("Wells Fargo") prime rate in effect on such day, the Federal funds effective rate in effect on such day plus 0.5% and the adjusted Eurodollar rate for a one-month interest period commencing on such day plus 1.0%. The adjusted Eurodollar rate is defined as the rate per annum obtained by dividing (1) the rate of interest offered to Wells Fargo on the London interbank market by (2) a percentage equal to 100% minus the stated maximum rate of all reserve requirements applicable to any member bank of the Federal Reserve System in respect of “Eurocurrency liabilities.”
Base Rate And Adjusted Rate Description	the base rate or the adjusted Eurodollar rate plus a margin of 1.75%
Long Term Debt Maturities Quarterly Repayments of Principal In First Four Quarters	$ 7,900,000
Long Term Debt Maturities Quarterly Repayments Of Principal In Quarters Five Through Twelve	11,800,000
Long Term Debt Maturities Quarterly Repayments Of Principal In Last Three Quarters	15,800,000
Credit Facility Capacity Available				581,300,000	600,000,000
Line of Credit Facility, Maximum Borrowing Capacity	125,000,000	125,000,000	100,000,000
Senior term notes					500,000,000
Debt Instrument, Basis Spread on Variable Rate	1.75%
Deferred financing costs	75,000	2,000,000
Capitalized Deferred financing costs associated with lenders		1,100,000
Leverage Ratio	2.03
Senior term note interest rate, period end	1.96%	2.00%
Line Of Credit Facility Minimum Borrowing Capacity Under A Swing Line					10,000,000
Debt Retirement Expense Recognized In Continuing Operations	47,000	865,000	2,100,000
Debt Retirement Expense Recognized In Continuing Operations After Tax			1,300,000
Amended Credit Facility Additional Revolving Commitment		25,000,000
Debt Instrument, Description of Variable Rate Basis	LIBOR
Proceeds from Issuance of Long-term Debt	50,000,000	150,000,000	500,000,000
Increase in Incremental Facilities	50,000,000
Fixed Charge Coverage Ratio	1.60%
Required Leverage Ratio	3.00
Incremental Facilities After Amendment	100,000,000
Long Term Obligations (Textual) [Abstract]
Senior term notes		100,000,000
Financing costs paid	$ 122,000	$ 2,944,000	$ 9,112,000
Revolving credit facility maturity date	Aug. 19, 2016
Amended Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	Base rate or adjusted Eurodollar rate
Senior Term Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Description Of Eurodollar Rate Basis	The adjusted Eurodollar rate is defined as the rate per annum obtained by dividing (1) the rate of interest offered to Wells Fargo on the London interbank market by (2) a percentage equal to 100% minus the stated maximum rate of all reserve requirements applicable to any member bank of the Federal Reserve System in respect of “Eurocurrency liabilities.”
Debt Instrument, Description of Variable Rate Basis	The base rate for the senior term notes is a rate per annum equal to the greatest of Wells Fargo’s prime rate in effect on such day, the Federal funds effective rate in effect on such day plus 0.5% and the adjusted Eurodollar rate for a one-month interest period commencing on such day plus 1.0%.
Senior Term Notes One [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%	1.75%
Debt Instrument, Interest Rate, Basis for Effective Rate	LIBOR plus 1.75%
Secured Seller Notes [Member]
Long Term Obligations (Textual) [Abstract]
Interest rates on notes payable maturities, minimum	9.00%
Interest rates on notes payable maturities, maximum	10.00%
Fixed Charge [Member]
Debt Instrument [Line Items]
Fixed charge coverage required ratio	1.20
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Aug. 19, 2016