Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Past Due Loans and Leases
30-59 Days Past Due	$ 31,418	$ 13,467
60-89 Days Past Due	2,973	4,511
Greater Than 90 Days and Accruing	654	453
Nonaccrual	112,807	112,026
Total Past Due and Nonaccrual Loans	147,852	130,457
Current	12,600,050	12,178,928
Total Loans and Leases	12,747,902	12,309,385	11,269,684
Commercial
Past Due Loans and Leases
30-59 Days Past Due	10,267	6,817
60-89 Days Past Due	980	1,003
Greater Than 90 Days and Accruing	7
Nonaccrual	19,584	19,888
Total Past Due and Nonaccrual Loans	30,838	27,708
Current	5,144,558	4,818,886
Total Loans and Leases	5,175,396	4,846,594
Commercial real estate mortgages
Past Due Loans and Leases
30-59 Days Past Due	3,953	5,838
Nonaccrual	21,071	21,948
Total Past Due and Nonaccrual Loans	25,024	27,786
Current	2,188,090	2,082,963
Total Loans and Leases	2,213,114	2,110,749	1,902,862
Residential mortgage
Past Due Loans and Leases
30-59 Days Past Due	525	662
60-89 Days Past Due	1,519	3,508
Greater Than 90 Days and Accruing	379	379
Nonaccrual	13,628	9,771
Total Past Due and Nonaccrual Loans	16,051	14,320
Current	3,789,756	3,748,898
Total Loans and Leases	3,805,807	3,763,218	3,603,058
Fixed
Past Due Loans and Leases
30-59 Days Past Due	525	662
60-89 Days Past Due		525
Greater Than 90 Days and Accruing	379	379
Nonaccrual	5,657	5,572
Total Past Due and Nonaccrual Loans	6,561	7,138
Current	1,531,537	1,574,658
Total Loans and Leases	1,538,098	1,581,796
Variable
Past Due Loans and Leases
60-89 Days Past Due	1,519	2,983
Nonaccrual	7,971	4,199
Total Past Due and Nonaccrual Loans	9,490	7,182
Current	2,258,219	2,174,240
Total Loans and Leases	2,267,709	2,181,422
Real estate construction
Past Due Loans and Leases
30-59 Days Past Due	16,288
Nonaccrual	48,964	50,876
Total Past Due and Nonaccrual Loans	65,252	50,876
Current	248,157	264,733
Total Loans and Leases	313,409	315,609	415,241
Construction
Past Due Loans and Leases
Nonaccrual	15,453	15,582
Total Past Due and Nonaccrual Loans	15,453	15,582
Current	206,184	202,279
Total Loans and Leases	221,637	217,861
Land
Past Due Loans and Leases
30-59 Days Past Due	16,288
Nonaccrual	33,511	35,294
Total Past Due and Nonaccrual Loans	49,799	35,294
Current	41,973	62,454
Total Loans and Leases	91,772	97,748
Equity lines of credit
Past Due Loans and Leases
30-59 Days Past Due	248
60-89 Days Past Due	74
Greater Than 90 Days and Accruing	268	74
Nonaccrual	8,831	8,669
Total Past Due and Nonaccrual Loans	9,421	8,743
Current	706,576	732,338
Total Loans and Leases	715,997	741,081	733,567
Installment loan
Past Due Loans and Leases
30-59 Days Past Due	137	150
60-89 Days Past Due	400
Nonaccrual	729	874
Total Past Due and Nonaccrual Loans	1,266	1,024
Current	124,527	131,623
Total Loans and Leases	125,793	132,647	146,779
Commercial Installment loan
Past Due Loans and Leases
Nonaccrual		4
Total Past Due and Nonaccrual Loans		4
Current	489	601
Total Loans and Leases	489	605
Consumer Installment loan
Past Due Loans and Leases
30-59 Days Past Due	137	150
60-89 Days Past Due	400
Nonaccrual	729	870
Total Past Due and Nonaccrual Loans	1,266	1,020
Current	124,038	131,022
Total Loans and Leases	125,304	132,042
Lease financing
Past Due Loans and Leases
Current	398,386	399,487
Total Loans and Leases	$ 398,386	$ 399,487