Deposits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deposits, by Type [Abstract]
Non-interest bearing demand	$ 1,495,309	$ 1,271,709
Interest bearing:
Demand	1,811,905	1,306,509
Savings	1,547,713	1,691,413
Time, $100 and over	594,712	681,047
Time, other	790,772	876,293
Total interest bearing	4,745,102	4,555,262
Total deposits	6,240,411	5,826,971
Time deposits obtained through Certificate of Deposit Account Registry Service (CDARS)	72,062	98,331
Contractual Maturities, Time Deposits, $100,000 or More [Abstract]
2013, Time, $100 and Over	437,597
2014, Time, $100 and Over	72,483
2015, Time, $100 and Over	33,646
2016, Time, $100 and Over	27,272
2017, Time, $100 and Over	23,714
Thereafter, Time, $100 and Over	0
Time Deposits, $100,000 or More	594,712	681,047
Time Deposits, Fiscal Year Maturity [Abstract]
2013, Time	999,439
2014, Time	176,243
2015, Time	79,030
2016, Time	63,412
2017, Time	67,357
Thereafter, Time	3
Time Deposits	1,385,484
Interest expense, time deposits, $100,000 or more	$ 6,951	$ 10,377	$ 18,595