Subsequent Event (Details) (USD $)	6 Months Ended
	Jun. 30, 2011
New Markets Tax Credits [Abstract]
Equity contributions to be made to the fund	$ 286,300,000
Net tax benefits and cash to be received from the fund.	304,600,000
Tax benefits in excess of capital contributions	71,800,000
Tax benefits not utilized	62,600,000
Future equity contributions [Abstract]
Future equity contributions - 2011	25,442,000
Future equity contributions - 2012	76,629,000
Future equity contributions - 2013	36,225,000
Future equity contributions - 2014	22,927,000
Future equity contributions - 2015	21,904,000
Future equity contributions - Thereafter	20,808,000
Future equity contributions - Total	203,935,000
Due to be paid within the next twelve months	62,500,000
Equity investments, imputed interest rate 6% [Abstract]
Principal payment schedule above:	$ 203,935,000