Loans and Allowance for Credit Losses Total Impaired Loans by Class Segments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	$ 112,644	$ 132,702
Unpaid principal balance, with related allowance	208,670	214,981
Unpaid Principal Balance	321,314	347,683
Recorded investment, with no related allowance	90,433	94,451
Recorded investment, with related allowance	172,122	175,889
Recorded Investment	262,555	270,340
Related Allowance	80,122	79,175
Real-estate commercial mortage [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	39,822	44,649
Unpaid principal balance, with related allowance	65,660	69,173
Recorded investment, with no related allowance	30,090	34,189
Recorded investment, with related allowance	53,485	55,443
Related Allowance	23,065	21,612
Commercial - Secured [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	37,359	40,409
Unpaid principal balance, with related allowance	44,282	52,660
Recorded investment, with no related allowance	32,713	30,112
Recorded investment, with related allowance	32,614	39,114
Related Allowance	16,633	17,187
Commercial - unsecured [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	0	132
Unpaid principal balance, with related allowance	1,420	2,142
Recorded investment, with no related allowance	0	131
Recorded investment, with related allowance	1,403	2,083
Related Allowance	1,051	1,597
Real-estate - home equity [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	110	300
Unpaid principal balance, with related allowance	13,759	12,843
Recorded investment, with no related allowance	110	300
Recorded investment, with related allowance	13,759	12,843
Related Allowance	8,754	8,380
Real-estate - residential mortgage [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	1,495	486
Unpaid principal balance, with related allowance	53,983	53,610
Recorded investment, with no related allowance	1,495	486
Recorded investment, with related allowance	53,983	53,610
Related Allowance	23,409	24,108
Construction - commercial residential [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	29,488	40,432
Unpaid principal balance, with related allowance	25,025	21,336
Recorded investment, with no related allowance	21,752	23,548
Recorded investment, with related allowance	13,160	9,831
Related Allowance	5,984	4,787
Construction - Commercial [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with no related allowance	4,370	6,294
Unpaid principal balance, with related allowance	3,988	2,602
Recorded investment, with no related allowance	4,273	5,685
Recorded investment, with related allowance	3,165	2,350
Related Allowance	903	1,146
Construction other [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with related allowance	490	576
Recorded investment, with related allowance	490	576
Related Allowance	279	326
Consumer - direct [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with related allowance	18	29
Recorded investment, with related allowance	18	29
Related Allowance	15	25
Leasing and other and overdrafts [Member]
Impaired Financing Receivables [Line Items]
Unpaid principal balance, with related allowance	45	10
Recorded investment, with related allowance	45	10
Related Allowance	$ 29	$ 7