Debt (5.125% Senior Notes) (Details) (USD $)				12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Aug. 31, 2010	Dec. 31, 2013 Senior Notes 5.125% Senior Notes	Mar. 19, 2013 Senior Notes 5.125% Senior Notes	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Redemption, Period 2018	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Redemption, Period 2019	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Redemption, Period 2020	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Redemption, Period 2021 and Thereafter	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Minimum	Dec. 31, 2013 Senior Notes 5.125% Senior Notes Maximum
Debt Instrument [Line Items]
Debt instrument, face amount					$ 300,000,000
Stated interest rate			8.47%		5.125%
Debt Covenant, Asset Proceeds, Excess Proceeds				25,000,000
Debt Covenant, Indenture Agreement, Period After Notice				60 days
Debt Instrument, Redemption Period, Change in Control, Percentage of Principal Amount Redeemable				101.00%
Redemption period, principal amount redeemable				35.00%
Capitalized loan costs	$ 33,100,000	$ 23,400,000		$ 6,800,000
Redemption period after closing of offering				0 years 0 months 90 days
Debt Instrument, Notice Period Prior to Redemption										0 years 0 months 30 days	0 years 0 months 60 days
Redemption price percentage				105.125%		102.563%	101.708%	100.854%	100.00%
Debt Instrument, Redemption Price, Percentage of Principal Remaining After Redemption				65.00%
Debt Instrument, Redemption Price Calculation Contributor, Percentage				100.00%