Loans and Leases and the Allowance for Credit Losses - Impaired Loans and Leases (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Recorded investment	$ 934,597	$ 1,072,026
Unpaid principal balance	1,151,963	1,354,133
Related allowance	101,286	132,682
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	118,513	159,913
Unpaid principal balance	145,123	191,733
Related allowance	25,530	33,829
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	205,205	199,922
Unpaid principal balance	252,346	244,183
Related allowance	24,104	23,641
Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	117,962	189,613
Unpaid principal balance	187,247	321,656
Related allowance	7,374	25,661
Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	94,076	96,562
Unpaid principal balance	101,231	100,401
Related allowance	3,104	6,836
Residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	183,328	189,793
Unpaid principal balance	212,470	218,267
Related allowance	6,537	3,521
Residential Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	144,092	160,245
Unpaid principal balance	181,011	200,708
Related allowance	15,000	17,000
Home Equity Lines and Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	13,258	12,360
Unpaid principal balance	14,372	13,567
Related allowance	3,408	2,254
Automobile [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	42,106	49,210
Unpaid principal balance	42,106	49,210
Related allowance	12,060	14,273
Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	16,057	14,408
Unpaid principal balance	16,057	14,408
Related allowance	4,169	5,667
Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	644,955	745,994
Unpaid principal balance	766,585	927,411
Related allowance	101,286	132,682
Impaired Financing Receivable With Related Allowance [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	93,568	127,282
Unpaid principal balance	114,572	149,534
Related allowance	25,530	33,829
Impaired Financing Receivable With Related Allowance [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	127,921	121,542
Unpaid principal balance	152,885	143,846
Related allowance	24,104	23,641
Impaired Financing Receivable With Related Allowance [Member] | Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	61,947	115,306
Unpaid principal balance	102,395	216,218
Related allowance	7,374	25,661
Impaired Financing Receivable With Related Allowance [Member] | Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	74,116	73,544
Unpaid principal balance	77,180	76,869
Related allowance	3,104	6,836
Impaired Financing Receivable With Related Allowance [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	100,287	103,451
Unpaid principal balance	118,572	121,819
Related allowance	6,537	3,521
Impaired Financing Receivable With Related Allowance [Member] | Residential Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	115,695	128,891
Unpaid principal balance	128,446	141,940
Related allowance	15,000	17,000
Impaired Financing Receivable With Related Allowance [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	13,258	12,360
Unpaid principal balance	14,372	13,567
Related allowance	3,408	2,254
Impaired Financing Receivable With Related Allowance [Member] | Automobile [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	42,106	49,210
Unpaid principal balance	42,106	49,210
Related allowance	12,060	14,273
Impaired Financing Receivable With Related Allowance [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	16,057	14,408
Unpaid principal balance	16,057	14,408
Related allowance	4,169	5,667
Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	289,642	326,032
Unpaid principal balance	385,378	426,722
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	24,945	32,631
Unpaid principal balance	30,551	42,199
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	77,284	78,380
Unpaid principal balance	99,461	100,337
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	56,015	74,307
Unpaid principal balance	84,852	105,438
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	19,960	23,018
Unpaid principal balance	24,051	23,532
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	83,041	86,342
Unpaid principal balance	93,898	96,448
Related allowance
Impaired Financing Receivable with No Related Allowance [Member] | Residential Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	28,397	31,354
Unpaid principal balance	52,565	58,768
Related allowance