Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 83,221		$ 85,509
Non-accrual TDRs	33,215	[1]	31,244	[1]
Total TDRs	116,436		116,753
Real-estate - residential mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	33,095		32,993
Real-estate commercial mortage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	28,421		34,672
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	8,898		5,624
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	11,125		10,564
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	1,537		1,518
Commercial - unsecured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	133		121
Consumer - direct [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 12		$ 17

[1] Included within non-accrual loans in the preceding table detailing non-performing assets.