Deposits (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Deposits [Line Items]
Noninterest-bearing demand	$ 2,588,034,000	$ 2,194,988,000
Interest-bearing demand	2,529,388,000	2,277,190,000
Savings and money market accounts	3,394,367,000	3,286,435,000
Time deposits	4,013,950,000	4,629,968,000
Total Deposits	12,525,739,000	12,388,581,000
Maturities of Time Deposits [Abstract]
2012	2,610,438,000
2013	798,373,000
2014	277,693,000
2015	195,809,000
2016	69,710,000
Thereafter	61,927,000
Total	4,013,950,000	4,629,968,000
Certificates of Deposit [Member]
Deposits [Line Items]
Time Deposits, $100,000 or More	$ 1,500,000,000	$ 1,700,000,000