Bank Line (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Lenders Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date	Sep. 30, 2014
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000,000
Line of Credit Facility, Covenant Terms	The Agreement requires the Company to maintain ratios defined in the Agreement, which include a consolidated total leverage ratio as of the end of any fiscal quarter not in excess of 2.50 to 1.00, a consolidated liquidity ratio of at least 1.25 to 1.00 and a consolidated interest coverage ratio at a minimum of 3.00 to 1.00.
Line of Credit Facility, Maximum Total Leverage Ratio Allowed	2.50
Line of Credit Facility, Minimum Consolidated Liquidity Ratio Required	1.25
Line of Credit Facility, Minimum Consolidated Interest Coverage Ratio Required	3
Line of Credit Facility, Amount Outstanding	0	0
Interest Cost	$ 0	$ 0
Eurodollar Rate Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Floor	2.50%
Line of Credit Facility, Interest Rate Cap	3.00%
Base Rate Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Floor	1.50%
Line of Credit Facility, Interest Rate Cap	2.00%
Bank of America Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	The Applicable Rate for Eurodollar Rate loans is based on the Company’s consolidated total leverage ratio (as defined in the Agreement) and is subject to a floor of 2.50% per annum and a cap of 3.00% per annum. Base Rate loans bear interest at a rate equal to the higher of the federal funds rate plus 0.50%, the prime rate of the Bank of America, N.A. plus the Applicable Rate or the Eurodollar Base Rate plus 1.0%. The Applicable Rate for Base Rate loans is subject to a floor of 1.50% per annum and a cap of 2.00% per annum.
Federal Funds Rate [Member] | Base Rate Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Eurodollar Rate [Member] | Base Rate Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%