Long-Term Debt (Senior Unsecured Debt) (Details) (USD $)	12 Months Ended			1 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2013	Mar. 31, 2012	Dec. 31, 2007
Debt Instrument [Line Items]
Payment On Senior Unsecured Notes		$ 281,490,000	$ 209,500,000
Loss on early extinguishment of debt		12,100,000	17,127,000
Amortization of deferred financing costs	4,870,000	5,187,000	9,086,000
Long-term debt	523,228,000	545,776,000
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes amount issued						550,000,000
Debt instrument interest rate						9.50%
Repayments of debt				275,000,000	200,000,000
Payment On Senior Unsecured Notes				282,000,000	213,500,000
Payment of debt extinguishment costs				6,500,000	9,500,000
Interest paid				500,000	4,000,000
Loss on early extinguishment of debt		8,600,000			11,500,000
Amortization of deferred financing costs		2,100,000			2,000,000
Long-term debt			$ 275,000,000