Subsequent Events Subsequent Events (Notes Redemption) (Details) (USD $)	3 Months Ended			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 2022 Unsecured Debt [Member]	Feb. 02, 2014 2022 Unsecured Debt [Member]	Jan. 03, 2014 2022 Unsecured Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Maturity Date, Description	January 3, 2014
Debt Instrument, Repurchase Amount					$ 1,083.32	$ 53,500,000.0
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				21.00%
Debt Instrument, Repurchase Date				Feb. 02, 2014
Debt Instrument, Face Amount					1,000.00
Long-term Debt		$ 1,200,472,000	$ 1,036,305,000		$ 196,500,000