Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 85,219		$ 66,175
Non-accrual TDRs	21,167	[1]	32,587	[1]
Total TDRs	106,386		98,762
Real-estate - residential mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	36,946		32,331
Real-estate commercial mortage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	32,198		22,425
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	4,671		3,449
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	10,190		7,645
Construction other [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	335		0
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	755		183
Commercial - unsecured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	124		132
Consumer - direct [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 0		$ 10

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