Allowance for Loan Losses Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Activity in the Allowance for Credit Losses by Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	$ 110,381	$ 113,903
Other adjustments	(1,333)	0
Reclassification to/from allowance for unfunded lending-related commitments	693	1,904
Charge-offs	(84,390)	(112,452)
Recoveries	9,588	9,106
Provision for credit losses	72,412	97,920
Allowance for loan losses at period end	107,351	110,381
Allowance for unfunded lending-related commitments at period end	14,647	13,231
Financing Receivable, Allowance for Credit Losses	121,998	123,612
Allowance for credit losses, Individually evaluated for impairment	27,657	34,111
Allowance for credit losses, Collectively evaluated for impairment	94,243	89,501
Loans acquired with deteriorated credit quality	98	0
Loans, Individually evaluated for impairment	204,545	226,538
Loans, Collectively evaluated for impairment	11,045,165	9,635,328
Loans, Loans acquired with deteriorated credit quality	579,233	659,511
Commercial [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	31,237	31,777
Other adjustments	(151)	0
Reclassification to/from allowance for unfunded lending-related commitments	45	1,606
Charge-offs	(22,405)	(31,951)
Recoveries	1,220	1,258
Provision for credit losses	18,848	28,547
Allowance for loan losses at period end	28,794	31,237
Allowance for unfunded lending-related commitments at period end	0	45
Financing Receivable, Allowance for Credit Losses	28,794	31,282
Allowance for credit losses, Individually evaluated for impairment	3,296	3,124
Allowance for credit losses, Collectively evaluated for impairment	25,471	28,158
Loans acquired with deteriorated credit quality	27	0
Loans, Individually evaluated for impairment	33,608	28,288
Loans, Collectively evaluated for impairment	2,876,180	2,461,604
Loans, Loans acquired with deteriorated credit quality	5,010	8,421
Commercial Real-Estate [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	56,405	62,618
Other adjustments	(1,054)	0
Reclassification to/from allowance for unfunded lending-related commitments	648	298
Charge-offs	(43,539)	(62,698)
Recoveries	6,635	1,386
Provision for credit losses	33,040	54,801
Allowance for loan losses at period end	52,135	56,405
Allowance for unfunded lending-related commitments at period end	14,647	13,186
Financing Receivable, Allowance for Credit Losses	66,782	69,591
Allowance for credit losses, Individually evaluated for impairment	20,481	27,007
Allowance for credit losses, Collectively evaluated for impairment	46,233	42,584
Loans acquired with deteriorated credit quality	68	0
Loans, Individually evaluated for impairment	139,878	171,372
Loans, Collectively evaluated for impairment	3,668,164	3,291,034
Loans, Loans acquired with deteriorated credit quality	56,076	51,855
Home Equity [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	7,712	6,213
Other adjustments	(4)	0
Reclassification to/from allowance for unfunded lending-related commitments	0	0
Charge-offs	(9,361)	(5,020)
Recoveries	428	64
Provision for credit losses	13,959	6,455
Allowance for loan losses at period end	12,734	7,712
Allowance for unfunded lending-related commitments at period end	0	0
Financing Receivable, Allowance for Credit Losses	12,734	7,712
Allowance for credit losses, Individually evaluated for impairment	2,569	2,963
Allowance for credit losses, Collectively evaluated for impairment	10,165	4,749
Loans acquired with deteriorated credit quality	0	0
Loans, Individually evaluated for impairment	14,590	15,778
Loans, Collectively evaluated for impairment	773,884	846,567
Loans, Loans acquired with deteriorated credit quality	0	0
Residential Real-Estate [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	5,028	5,107
Other adjustments	(124)	0
Reclassification to/from allowance for unfunded lending-related commitments	0	0
Charge-offs	(4,060)	(4,115)
Recoveries	22	10
Provision for credit losses	4,694	4,026
Allowance for loan losses at period end	5,560	5,028
Allowance for unfunded lending-related commitments at period end	0	0
Financing Receivable, Allowance for Credit Losses	5,560	5,028
Allowance for credit losses, Individually evaluated for impairment	1,169	992
Allowance for credit losses, Collectively evaluated for impairment	4,388	4,036
Loans acquired with deteriorated credit quality	3	0
Loans, Individually evaluated for impairment	14,810	10,792
Loans, Collectively evaluated for impairment	351,547	338,804
Loans, Loans acquired with deteriorated credit quality	856	693
Premium Finance Receivable [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	7,214	6,319
Other adjustments	0	0
Reclassification to/from allowance for unfunded lending-related commitments	0	0
Charge-offs	(3,780)	(6,892)
Recoveries	940	6,018
Provision for credit losses	1,722	1,769
Allowance for loan losses at period end	6,096	7,214
Allowance for unfunded lending-related commitments at period end	0	0
Financing Receivable, Allowance for Credit Losses	6,096	7,214
Allowance for credit losses, Individually evaluated for impairment	0	0
Allowance for credit losses, Collectively evaluated for impairment	6,096	7,214
Loans acquired with deteriorated credit quality	0	0
Loans, Individually evaluated for impairment	0	0
Loans, Collectively evaluated for impairment	3,198,563	2,509,216
Loans, Loans acquired with deteriorated credit quality	514,459	598,463
Indirect Consumer [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	645	526
Other adjustments	0	0
Reclassification to/from allowance for unfunded lending-related commitments	0	0
Charge-offs	(221)	(244)
Recoveries	103	220
Provision for credit losses	(260)	143
Allowance for loan losses at period end	267	645
Allowance for unfunded lending-related commitments at period end	0	0
Financing Receivable, Allowance for Credit Losses	267	645
Allowance for credit losses, Individually evaluated for impairment	0	5
Allowance for credit losses, Collectively evaluated for impairment	267	640
Loans acquired with deteriorated credit quality	0	0
Loans, Individually evaluated for impairment	53	75
Loans, Collectively evaluated for impairment	77,280	64,470
Loans, Loans acquired with deteriorated credit quality	0	0
Consumer and Other [Member]
Allowance for Loan Losses [Roll Forward]
Allowance for loan losses at beginning of period	2,140	1,343
Other adjustments	0	0
Reclassification to/from allowance for unfunded lending-related commitments	0	0
Charge-offs	(1,024)	(1,532)
Recoveries	240	150
Provision for credit losses	409	2,179
Allowance for loan losses at period end	1,765	2,140
Allowance for unfunded lending-related commitments at period end	0	0
Financing Receivable, Allowance for Credit Losses	1,765	2,140
Allowance for credit losses, Individually evaluated for impairment	142	20
Allowance for credit losses, Collectively evaluated for impairment	1,623	2,120
Loans acquired with deteriorated credit quality	0	0
Loans, Individually evaluated for impairment	1,606	233
Loans, Collectively evaluated for impairment	99,547	123,633
Loans, Loans acquired with deteriorated credit quality	$ 2,832	$ 79