Long-Term Debt (Narrative) (Details) (USD $)			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Line of Credit [Member]	Dec. 31, 2013 Unsecured Debt [Member]	Dec. 31, 2013 Secured Debt [Member]	Dec. 31, 2013 Capital Lease Obligations [Member]	Dec. 31, 2013 Other Debt Obligations [Member]	Dec. 31, 2013 Maximum [Member] Line of Credit [Member]	Dec. 31, 2013 Minimum [Member] Line of Credit [Member]	Dec. 31, 2013 Period from current report date to November 30, 2015 Unsecured Debt [Member]	Dec. 31, 2013 Period from January 1, 2012 through November 7, 2012 Secured Debt [Member]
Long-term Debt, by Maturity [Abstract]
Repayments of Principal in Next Twelve Months	$ 20,844,000
Repayments of Principal after Year Five	272,185,000
Long-term Debt, Maturing in Years Two and Three [Abstract]
Repayments of Principal in Year Two	17,751,000
Repayments of Principal in Year Three	14,903,000
Long-term Debt, Maturing in Years Four and Five [Abstract]
Repayments of Principal in Year Four	13,422,000
Repayments of Principal in Year Five	265,037,000
Credit Facility
Borrowing capacity of new revolving credit agreement			475,000,000
Line of Credit Facility, Expiration Date			Jun. 01, 2018
Debt instruments interest rate base rate plus								1.00%	0.25%
Debt instruments interest rate Libor plus								2.00%	1.25%
Unused capacity commitment fee, percentage								0.40%	0.25%
Senior Unsecured Debt
Unsecured Debt	250,000,000	250,000,000
Debt Instrument, Interest Rate, Stated Percentage				5.625%	8.04%						6.04%
Debt Instrument, Maturity Date				Nov. 30, 2020	May 28, 2020	Dec. 31, 2026	Nov. 30, 2025
Redeemable Principal Percentage				35.00%
Future Redemption Price of Debt During Eligibility Period, as a Percentage of Principal Amount										105.625%
Senior Secured Debt
Senior Secured Notes	69,643,000	75,000,000
Debt Instrument, Interest Rate, Stated Percentage				5.625%	8.04%						6.04%
Debt Instrument, Maturity Date				Nov. 30, 2020	May 28, 2020	Dec. 31, 2026	Nov. 30, 2025
Debt Instrument, Interest Rate Increase					2.00%
Other Long-term Debt [Abstract]
Book Value of Collateralized By Certain Assets							$ 74,150,000