Condensed Consolidating Statement of Condition (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Assets
Cash And Due From Banks	$ 388,041	$ 439,363	$ 515,338	$ 535,282
Money market investments	1,071,939	1,085,580
Trading Securities	294,082	314,525
Available For Sale Securities	5,114,636	5,084,201
Investment securities held-to-maturity, at amortized cost	141,632	142,817
Other investment securities, at lower of cost or realizable value	218,582	185,443
Loans held-for-sale, at lower of cost or fair value	190,852	354,468
Loans held-in-portfolio:
Loans held-in-portfolio	21,615,754	21,080,005
Covered Loans	3,199,998	3,755,972
Less- Unearned Income	94,095	96,813
Allowance for loan losses	635,219	730,607
Total loans held-in-portfolio, net	24,086,438	24,008,557
FDIC loss share asset	1,379,342	1,399,098	1,631,594	1,915,128
Premises and equipment, net	527,014	535,793
Interest Receivable	143,905	125,728
Servicing Asset At Fair Value Amount	153,444	154,430	155,711	151,323
Other Assets	1,935,426	1,569,578
Goodwill	647,757	647,757	647,757	648,350
Intangible Assets Net Excluding Goodwill	49,359	54,295
Total assets	36,684,594	36,507,535
Deposits Abstract
Noninterest Bearing Deposit Liabilities	5,856,066	5,794,629
Interest Bearing Deposit Liabilities	20,903,362	21,205,984
Total deposits	26,759,428	27,000,613
Securities Sold under Agreements to Repurchase	1,672,705	2,016,752
Other short-term borrowings	1,226,200	636,200
Notes Payable	1,795,766	1,777,721
Other liabilities	1,035,459	966,249
Liabilities	32,489,558	32,397,535
Stockholders Equity Abstract
Preferred stock	50,160	50,160
Common stock	1,033	1,032
Surplus	4,153,525	4,150,294
Accumulated deficit	217,126	11,826
Treasury stock	(769)	(444)
Accumulated other comprehensive (loss) income, net of tax	(226,039)	(102,868)
Total stockholders' equity	4,195,036	4,110,000	4,021,237	3,918,753
Liabilities And Stockholders Equity	36,684,594	36,507,535
Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	158,920	266,844
Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Covered Loans	3,199,998	3,755,972
Real Estate Acquired Through Foreclosure	183,225	139,058
Parent Company [Member]
Assets
Cash And Due From Banks	1,435	1,103	9,269	6,365
Money market investments	40,489	18,574
Trading Securities	1,425	1,259
Available For Sale Securities	4,836	42,383
Investment securities held-to-maturity, at amortized cost	185,000	185,000
Other investment securities, at lower of cost or realizable value	10,850	10,850
Investment in subsidiaries	4,259,281	4,285,957
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Loans held-in-portfolio	424,761	286,080
Covered Loans	0	0
Less- Unearned Income	0	0
Allowance for loan losses	46	241
Total loans held-in-portfolio, net	424,715	285,839
FDIC loss share asset	0	0
Premises and equipment, net	2,343	2,495
Interest Receivable	93	1,675
Servicing Asset At Fair Value Amount	0	0
Other Assets	114,687	112,775
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	554	554
Total assets	5,045,708	4,948,464
Deposits Abstract
Noninterest Bearing Deposit Liabilities	0	0
Interest Bearing Deposit Liabilities	0	0
Total deposits	0	0
Securities Sold under Agreements to Repurchase	0	0
Other short-term borrowings	0	0
Notes Payable	806,873	790,282
Subordinated Debt	0	0
Other liabilities	43,799	48,182
Liabilities	850,672	838,464
Stockholders Equity Abstract
Preferred stock	50,160	50,160
Common stock	1,033	1,032
Surplus	4,144,998	4,141,767
Accumulated deficit	225,653	20,353
Treasury stock	(769)	(444)
Accumulated other comprehensive (loss) income, net of tax	(226,039)	(102,868)
Total stockholders' equity	4,195,036	4,110,000
Liabilities And Stockholders Equity	5,045,708	4,948,464
Parent Company [Member] | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	0	0
Parent Company [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	0	0
Non Guarantor Subsidiaries Member
Assets
Cash And Due From Banks	620	624	628	932
Money market investments	1,118	867
Trading Securities	0	0
Available For Sale Securities	0	0
Investment securities held-to-maturity, at amortized cost	0	0
Other investment securities, at lower of cost or realizable value	4,492	4,492
Investment in subsidiaries	1,643,437	1,653,636
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Loans held-in-portfolio	0	0
Covered Loans	0	0
Less- Unearned Income	0	0
Allowance for loan losses	0	0
Total loans held-in-portfolio, net	0	0
FDIC loss share asset	0	0
Premises and equipment, net	114	115
Interest Receivable	112	112
Servicing Asset At Fair Value Amount	0	0
Other Assets	14,924	12,614
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	0	0
Total assets	1,664,817	1,672,460
Deposits Abstract
Noninterest Bearing Deposit Liabilities	0	0
Interest Bearing Deposit Liabilities	0	0
Total deposits	0	0
Securities Sold under Agreements to Repurchase	0	0
Other short-term borrowings	0	0
Notes Payable	382,646	385,609
Subordinated Debt	0	0
Other liabilities	42,104	42,120
Liabilities	424,750	427,729
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	2	2
Surplus	4,224,008	4,206,708
Accumulated deficit	(2,982,728)	(3,012,365)
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	(1,215)	50,386
Total stockholders' equity	1,240,067	1,244,731
Liabilities And Stockholders Equity	1,664,817	1,672,460
Non Guarantor Subsidiaries Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	0	0
Non Guarantor Subsidiaries Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	0	0
Other Subsidiaries [Member]
Assets
Cash And Due From Banks	387,956	439,552	515,541	534,796
Money market investments	1,053,250	1,067,006
Trading Securities	292,657	313,266
Available For Sale Securities	5,109,800	5,058,786
Investment securities held-to-maturity, at amortized cost	141,632	142,817
Other investment securities, at lower of cost or realizable value	203,240	170,101
Investment in subsidiaries	0	0
Loans held-for-sale, at lower of cost or fair value	190,852	354,468
Loans held-in-portfolio:
Loans held-in-portfolio	21,613,993	21,050,205
Covered Loans	3,199,998	3,755,972
Less- Unearned Income	94,095	96,813
Allowance for loan losses	635,173	730,366
Total loans held-in-portfolio, net	24,084,723	23,978,998
FDIC loss share asset	1,379,342	1,399,098
Premises and equipment, net	524,557	533,183
Interest Receivable	143,740	124,266
Servicing Asset At Fair Value Amount	153,444	154,430
Other Assets	1,863,035	1,457,852
Goodwill	647,757	647,757
Intangible Assets Net Excluding Goodwill	48,805	53,741
Total assets	36,566,935	36,301,223
Deposits Abstract
Noninterest Bearing Deposit Liabilities	5,858,128	5,796,992
Interest Bearing Deposit Liabilities	20,913,475	21,216,085
Total deposits	26,771,603	27,013,077
Securities Sold under Agreements to Repurchase	1,694,505	2,016,752
Other short-term borrowings	1,649,200	866,500
Notes Payable	606,247	601,830
Subordinated Debt	185,000	185,000
Other liabilities	997,740	923,138
Liabilities	31,904,295	31,606,297
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	55,628	55,628
Surplus	5,859,926	5,859,926
Accumulated deficit	(1,025,312)	(1,114,802)
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	(227,602)	(105,826)
Total stockholders' equity	4,662,640	4,694,926
Liabilities And Stockholders Equity	36,566,935	36,301,223
Other Subsidiaries [Member] | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	158,920	266,844
Other Subsidiaries [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	183,225	139,058
Consolidation Eliminations Member
Assets
Cash And Due From Banks	(1,970)	(1,916)	(10,100)	(6,811)
Money market investments	(22,918)	(867)
Trading Securities	0	0
Available For Sale Securities	0	(16,968)
Investment securities held-to-maturity, at amortized cost	(185,000)	(185,000)
Other investment securities, at lower of cost or realizable value	0	0
Investment in subsidiaries	(5,902,718)	(5,939,593)
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Loans held-in-portfolio	(423,000)	(256,280)
Covered Loans	0	0
Less- Unearned Income	0	0
Allowance for loan losses	0	0
Total loans held-in-portfolio, net	(423,000)	(256,280)
FDIC loss share asset	0	0
Premises and equipment, net	0	0
Interest Receivable	(40)	(325)
Servicing Asset At Fair Value Amount	0	0
Other Assets	(57,220)	(13,663)
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	0	0
Total assets	(6,592,866)	(6,414,612)
Deposits Abstract
Noninterest Bearing Deposit Liabilities	(2,062)	(2,363)
Interest Bearing Deposit Liabilities	(10,113)	(10,101)
Total deposits	(12,175)	(12,464)
Securities Sold under Agreements to Repurchase	(21,800)	0
Other short-term borrowings	(423,000)	(230,300)
Notes Payable	0	0
Subordinated Debt	(185,000)	(185,000)
Other liabilities	(48,184)	(47,191)
Liabilities	(690,159)	(474,955)
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	(55,630)	(55,630)
Surplus	(10,075,407)	(10,058,107)
Accumulated deficit	3,999,513	4,118,640
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	228,817	55,440
Total stockholders' equity	(5,902,707)	(5,939,657)
Liabilities And Stockholders Equity	(6,592,866)	(6,414,612)
Consolidation Eliminations Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	0	0
Consolidation Eliminations Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Real Estate Acquired Through Foreclosure	$ 0	$ 0