Long-Term Debt (Senior Notes) (Details) (USD $)	0 Months Ended	12 Months Ended				0 Months Ended		12 Months Ended		0 Months Ended	12 Months Ended
	Sep. 25, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009	Jan. 31, 2013 3.85% Notes, Payable February 1, 2023 [Member]	Jan. 17, 2006 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2013 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2012 6.125% Notes, Payable January 15, 2016 [Member]	Apr. 16, 2012 7.20% Senior Notes, Payable April 15, 2012 [Member]	Dec. 31, 2013 7.20% Senior Notes, Payable April 15, 2012 [Member]	Dec. 31, 2012 7.20% Senior Notes, Payable April 15, 2012 [Member]	Dec. 31, 2002 7.20% Senior Notes, Payable April 15, 2012 [Member]
Debt Instrument [Line Items]
Increase (Decrease) on Interest Rate		0.05%			(0.75%)
Aggregate principal amount of debts						$ 600,000,000	$ 900,000,000						$ 400,000,000
Interest rate percentage						3.85%	6.125%	6.125%	6.125%		7.20%	7.20%	7.20%
Payment of financing costs	1,836,000					6,000,000
Notes payable, maturity date							Jan. 15, 2016	Jan. 15, 2016	Jan. 15, 2016		Apr. 15, 2012	Apr. 15, 2012
Increase in interest rate from rating agency downgrade									0.25%
Maximum increase in interest rate per agency from rating agency downgrade									1.00%
Increase in interest expense per quarter for .25% increase in notes per $100,000 of outstanding notes		92,246,000	74,713,000	101,617,000					63,000
Incremental increase in outstanding notes							100,000,000
Remaining outstanding senior notes repaid												63,730,000
Repurchase price as percentage of principal amount of senior notes												102.72%
Repayments of secured debt										336,270,000
Increase accrued interest										$ 12,106,000