Financial Instruments with Off-Balance Sheet Risk (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Entity Information [Line Items]
Credit Extension Commitments	$ 1,176,789
Credit Extension Commitments, Beyond One Year	304,030
Standby Letters of Credit
Entity Information [Line Items]
Credit Extension Commitments	71,407
Unused Credit Card Lines
Entity Information [Line Items]
Credit Extension Commitments	$ 362,247