Debt, Non-Bank Debt (Details) (USD $)	1 Months Ended		1 Months Ended		1 Months Ended										1 Months Ended				0 Months Ended	1 Months Ended									1 Months Ended
	Jan. 31, 2013 Senior Notes [Member] Senior Notes Due In January 2013 [Member]	Dec. 31, 2013 Senior Notes [Member] Senior Notes Due In January 2013 [Member]	Jun. 30, 2013 Senior Notes [Member] Senior Notes Due In June 2013 [Member]	Dec. 31, 2013 Senior Notes [Member] Senior Notes Due In June 2013 [Member]	Feb. 28, 2011 Senior Notes [Member] Senior Notes Due In February 2011 [Member]	May 31, 2011 Senior Notes [Member] Senior Notes Due In May 2011 [Member]	Dec. 31, 2013 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1997 [Member]	Mar. 31, 2012 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1997 [Member]	Dec. 31, 2013 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1998 [Member]	Mar. 31, 2012 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1998 [Member]	Dec. 31, 2013 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1999 [Member]	Mar. 31, 2012 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 1999 [Member]	Dec. 31, 2013 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 2001 [Member]	Mar. 31, 2012 Revenue Bonds [Member] Tax Exempt Waste Disposal Revenue Bonds Series 2001 [Member]	Apr. 30, 2012 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997A [Member]	Dec. 31, 2013 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997A [Member]	Mar. 31, 2012 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997A [Member]	Apr. 30, 2011 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997A [Member]	May 03, 2012 Revenue Bonds [Member] Industrial Revenue Bonds Tax Exempt Refunding Bonds [Member]	Dec. 31, 2011 Revenue Bonds [Member] Industrial Revenue Bonds Tax Exempt Refunding Bonds [Member]	Apr. 30, 2011 Revenue Bonds [Member] Industrial Revenue Bonds Tax Exempt Refunding Bonds [Member]	Jun. 30, 2012 Revenue Bonds [Member] Gulf Opportunity Zone Revenue Bonds Series 2010 [Member]	Feb. 28, 2011 Revenue Bonds [Member] Gulf Opportunity Zone Revenue Bonds Series 2010 [Member]	Dec. 31, 2013 Revenue Bonds [Member] Gulf Opportunity Zone Revenue Bonds Series 2010 [Member]	Dec. 31, 2011 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997B [Member]	Apr. 30, 2011 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997B [Member]	Dec. 31, 2011 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997C [Member]	Apr. 30, 2011 Revenue Bonds [Member] Tax Exempt Revenue Refunding Bonds Series 1997C [Member]	Apr. 30, 2012 Notes [Member] Notes Due In 2012 [Member]
Non-Bank Debt (Textual)
Debt repayments	$ 180,000,000		$ 300,000,000		$ 210,000,000	$ 200,000,000									$ 4,000,000				$ 108,000,000	$ 56,000,000	$ 8,000,000		$ 300,000,000						$ 750,000,000
Interest rate of notes in percentage	6.70%	6.70%	4.75%	4.75%	6.75%	6.125%	5.60%	5.60%	5.60%	5.60%	5.70%	5.70%	6.65%	6.65%	5.45%	5.45%	5.45%	5.45%				4.00%		4.00%	5.40%	5.40%	5.40%	5.40%	6.875%
Redemption value in percentage																			100.00%	100.00%
Proceeds from advances for construction																						$ 300,000,000
Debt instrument, maturity date (month, day, year)																						Dec. 01, 2040
Debt instrument, mandatory tender date																						Jun. 01, 2022