Debt Level 4 (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	May 28, 2013	Dec. 31, 2013 Aggregate principal amount [Member]	Dec. 31, 2013 Discount (premium) [Member]	Dec. 31, 2013 Unsecured Debt [Member]	Dec. 31, 2012 Unsecured Debt [Member]	Dec. 31, 2013 Unsecured Debt [Member] February 2013 [Member]	Dec. 31, 2012 Unsecured Debt [Member] February 2013 [Member]	Dec. 31, 2013 Unsecured Debt [Member] July 2014 [Member]	Dec. 31, 2012 Unsecured Debt [Member] July 2014 [Member]	Dec. 31, 2013 Unsecured Debt [Member] April 2015 [Member]	Dec. 31, 2012 Unsecured Debt [Member] April 2015 [Member]	Dec. 31, 2013 Unsecured Debt [Member] April 2016 [Member]	Dec. 31, 2012 Unsecured Debt [Member] April 2016 [Member]	Dec. 31, 2013 Unsecured Debt [Member] July 2016 [Member]	Dec. 31, 2012 Unsecured Debt [Member] July 2016 [Member]	Dec. 31, 2013 Unsecured Debt [Member] June 2017 [Member]	Dec. 31, 2012 Unsecured Debt [Member] June 2017 [Member]	Dec. 31, 2013 Unsecured Debt [Member] October 2018 [Member]	Dec. 31, 2012 Unsecured Debt [Member] October 2018 [Member]	Dec. 31, 2013 Unsecured Debt [Member] April 2019 [Member]	Dec. 31, 2012 Unsecured Debt [Member] April 2019 [Member]	Dec. 31, 2013 Unsecured Debt [Member] May 2019 [Member]	Dec. 31, 2012 Unsecured Debt [Member] May 2019 [Member]	Dec. 31, 2013 Unsecured Debt [Member] November 2020 [Member]	Dec. 31, 2012 Unsecured Debt [Member] November 2020 [Member]	Dec. 31, 2013 Unsecured Debt [Member] November 2021 [Member]	Dec. 31, 2012 Unsecured Debt [Member] November 2021 [Member]	Dec. 31, 2013 Unsecured Debt [Member] January 2022 [Member]	Dec. 31, 2012 Unsecured Debt [Member] January 2022 [Member]	Dec. 31, 2013 Unsecured Debt [Member] April 2027 [Member]	Dec. 31, 2012 Unsecured Debt [Member] April 2027 [Member]	Dec. 31, 2013 Unsecured Debt [Member] March 2016 [Member]	Dec. 31, 2012 Unsecured Debt [Member] March 2016 [Member]	Feb. 10, 2014 Unsecured Debt [Member] July 2018 [Member]	Dec. 31, 2013 Unsecured Debt [Member] July 2018 [Member]	Dec. 31, 2012 Unsecured Debt [Member] July 2018 [Member]	Dec. 31, 2013 Capital Lease Obligations [Member]	Dec. 31, 2012 Capital Lease Obligations [Member]	Dec. 31, 2013 Mortgages [Member]	Dec. 31, 2012 Mortgages [Member]
Debt Instrument [Line Items]
Senior Notes									$ 0	$ 4,757,000			$ 136,465,000	$ 136,465,000	$ 197,377,000	$ 197,377,000			$ 295,000,000	$ 295,000,000	$ 250,000,000	$ 250,000,000	$ 200,000,000	$ 0	$ 250,000,000	$ 250,000,000	$ 200,000,000	$ 200,000,000	$ 150,000,000	$ 150,000,000	$ 425,000,000	$ 0	$ 200,000,000	$ 200,000,000
Notes Payable to Bank, Noncurrent	600,000,000	0		600,000,000
Convertible Debt											85,256,000	0					46,279,000	0
Bank credit facility due March 2016	86,600,000																																		0	86,600,000	140,000,000	30,000,000	0
Obligations under capital leases																																								189,697,000	176,445,000
Mortgage notes and other debt, maturities through 2047																																										4,752,000	5,698,000
Unamortized pricing discounts and other							42,084,000	(4,292,000)
Total debt	3,301,910,000	1,948,050,000			3,259,826,000	42,084,000
Current maturities of long-term debt	123,738,000	32,072,000
Debt instrument, unamortized discount (premium), net, current portion	(22,624,000)	643,000
Less current maturities	146,362,000	31,429,000
Total long-term debt	3,155,548,000	1,916,621,000
Debt, Weighted Average Interest Rate	5.25%	6.28%
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	76.00%	87.00%
2012	146,362,000				123,738,000	22,624,000
2013	191,264,000				180,742,000	10,522,000
2014	266,334,000				260,387,000	5,947,000
2015	336,720,000				335,221,000	1,499,000
2016	917,457,000				915,708,000	1,749,000
2017 and thereafter	1,443,773,000				1,444,030,000	(257,000)
Line of Credit Facility, Maximum Borrowing Capacity	500,000,000
Letters of Credit, Maximum Borrowing Capacity	175,000,000		175,000,000
Interest Paid	125,022,000	131,723,000	129,105,000
Payments in 2012	164,871,000
Payments in 2013	156,580,000
Payments in 2014	143,296,000
Payments in 2015	127,496,000
Payments in 2016	112,415,000
Payments in 2017 and thereafter	$ 255,429,000