Debt (6.625% Senior Notes) (Details) (USD $)	12 Months Ended					1 Months Ended	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jan. 01, 2012	Aug. 31, 2010	Dec. 31, 2012 6.625% Senior Notes	Feb. 10, 2011 Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Senior Notes 6.625% Senior Notes	Mar. 19, 2013 Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Redemption, Period 2016 Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Redemption, Period 2017 Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Redemption, Period 2018 Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Redemption, Period 2019 and Thereafter Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Minimum Senior Notes 6.625% Senior Notes	Dec. 31, 2013 Maximum Senior Notes 6.625% Senior Notes
Debt Instrument [Line Items]
Debt instrument, face amount						$ 300,000,000
Stated interest rate				8.47%		6.625%	6.625%	6.625%
Redemption period after closing of offering							90 days
Debt Instrument, Notice Period Prior to Redemption													30 days	60 days
Debt Covenant, Asset Proceeds, Excess Proceeds							25,000,000
Debt Instrument, Redemption Period, Change in Control, Percentage of Principal Amount Redeemable							101.00%
Debt Instrument, Redemption Price Including Accrued Interest And Liquidated Damages, Percentage							106.625%
Debt Instrument, Redemption Price, Percentage of Principal Remaining After Redemption							65.00%
Redemption period, principal amount redeemable							35.00%
Proceeds from long term debt	1,238,000,000	358,000,000	835,395,000			293,300,000
Borrowing under amended senior credit facility					$ 150,000,000
Redemption price percentage							100.00%		103.313%	102.208%	101.104%	100.00%