Allowance For Loan Losses And Reserve For Unfunded Commitments (Allowance For Loan Losses) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Balance at beginning of period	$ 183,844		$ 218,237		$ 191,594		$ 222,821
Loans charged-off	(33,872)		(45,317)		(73,598)		(87,608)
Recoveries on loans previously charged-off	6,927		1,641		11,268		2,642
Net charge-offs	(26,945)		(43,676)		(62,330)		(84,966)
Provision for loan losses	17,403		31,725		45,038		68,431
Balance at end of period	174,302		206,286		174,302		206,286
Ending balance, Allowance for credit losses individually evaluated for impairment	58,097	[1]	71,686	[1]	58,097	[1]	71,686	[1]	69,944
Ending balance, Allowance for credit losses collectively evaluated for impairment	116,205		134,600		116,205		134,600
Ending balance, loans individually evaluated for impairment	307,029	[1]	455,062	[1]	307,029	[1]	455,062	[1]	360,761
Ending balance, loans collectively evaluated for impairment	9,129,206		8,217,580		9,129,206		8,217,580
Total Loans	9,436,235		8,672,642		9,436,235		8,672,642		9,008,561
Commercial Loan [Member]
Balance at beginning of period	59,911		64,695		60,663		70,115
Loans charged-off	(7,769)		(10,512)		(17,318)		(14,712)
Recoveries on loans previously charged-off	634		707		2,313		1,172
Net charge-offs	(7,135)		(9,805)		(15,005)		(13,540)
Provision for loan losses	12,409		1,462		19,527		(223)
Balance at end of period	65,185		56,352		65,185		56,352
Ending balance, Allowance for credit losses individually evaluated for impairment	17,975	[1]	10,352	[1]	17,975	[1]	10,352	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	47,210		46,000		47,210		46,000
Ending balance, loans individually evaluated for impairment	142,059	[1]	114,184	[1]	142,059	[1]	114,184	[1]
Ending balance, loans collectively evaluated for impairment	5,766,552		4,758,973		5,766,552		4,758,973
Total Loans	5,908,611		4,873,157		5,908,611		4,873,157
Commercial Real Estate [Member]
Balance at beginning of period	97,021		114,186		94,905		110,853
Loans charged-off	(17,924)		(25,402)		(43,204)		(54,811)
Recoveries on loans previously charged-off	4,150		511		6,032		783
Net charge-offs	(13,774)		(24,891)		(37,172)		(54,028)
Provision for loan losses	1,239		22,240		26,753		54,710
Balance at end of period	84,486		111,535		84,486		111,535
Ending balance, Allowance for credit losses individually evaluated for impairment	30,786	[1]	44,535	[1]	30,786	[1]	44,535	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	53,700		67,000		53,700		67,000
Ending balance, loans individually evaluated for impairment	132,421	[1]	230,277	[1]	132,421	[1]	230,277	[1]
Ending balance, loans collectively evaluated for impairment	2,491,321		2,467,143		2,491,321		2,467,143
Total Loans	2,623,742		2,697,420		2,623,742		2,697,420
Construction Loans [Member]
Balance at beginning of period	3,180		24,098		12,852		19,778
Loans charged-off	(828)		(8,275)		(2,073)		(8,337)
Recoveries on loans previously charged-off	1,664		56		1,705		153
Net charge-offs	836		(8,219)		(368)		(8,184)
Provision for loan losses	(1,235)		1,852		(9,703)		6,137
Balance at end of period	2,781		17,731		2,781		17,731
Ending balance, Allowance for credit losses individually evaluated for impairment	146	[1]	8,131	[1]	146	[1]	8,131	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	2,635		9,600		2,635		9,600
Ending balance, loans individually evaluated for impairment	555	[1]	46,152	[1]	555	[1]	46,152	[1]
Ending balance, loans collectively evaluated for impairment	170,459		319,909		170,459		319,909
Total Loans	171,014		366,061		171,014		366,061
Residential Real Estate [Member]
Balance at beginning of period	6,560		5,973		6,376		5,321
Loans charged-off	(1,006)		(186)		(2,090)		(572)
Recoveries on loans previously charged-off	2		40		13		42
Net charge-offs	(1,004)		(146)		(2,077)		(530)
Provision for loan losses	1,273		1,238		2,530		2,274
Balance at end of period	6,829		7,065		6,829		7,065
Ending balance, Allowance for credit losses individually evaluated for impairment	1,629	[1]	1,665	[1]	1,629	[1]	1,665	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	5,200		5,400		5,200		5,400
Ending balance, loans individually evaluated for impairment	11,902	[1]	19,663	[1]	11,902	[1]	19,663	[1]
Ending balance, loans collectively evaluated for impairment	318,352		281,587		318,352		281,587
Total Loans	330,254		301,250		330,254		301,250
Home Equity Line of Credit [Member]
Balance at beginning of period	6,601		4,833		4,022		5,764
Loans charged-off	(4)		(508)		(487)		(1,955)
Recoveries on loans previously charged-off	314		15		340		25
Net charge-offs	310		(493)		(147)		(1,930)
Provision for loan losses	153		2,286		3,189		2,792
Balance at end of period	7,064		6,626		7,064		6,626
Ending balance, Allowance for credit losses individually evaluated for impairment	2,864	[1]	3,126	[1]	2,864	[1]	3,126	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	4,200		3,500		4,200		3,500
Ending balance, loans individually evaluated for impairment	13,684	[1]	12,911	[1]	13,684	[1]	12,911	[1]
Ending balance, loans collectively evaluated for impairment	160,447		177,780		160,447		177,780
Total Loans	174,131		190,691		174,131		190,691
Consumer Loan [Member]
Balance at beginning of period	10,571		4,452		12,776		10,990
Loans charged-off	(6,341)		(434)		(8,426)		(7,221)
Recoveries on loans previously charged-off	163		312		865		467
Net charge-offs	(6,178)		(122)		(7,561)		(6,754)
Provision for loan losses	3,564		2,647		2,742		2,741
Balance at end of period	7,957		6,977		7,957		6,977
Ending balance, Allowance for credit losses individually evaluated for impairment	4,697	[1]	3,877	[1]	4,697	[1]	3,877	[1]
Ending balance, Allowance for credit losses collectively evaluated for impairment	3,260		3,100		3,260		3,100
Ending balance, loans individually evaluated for impairment	6,408	[1]	31,875	[1]	6,408	[1]	31,875	[1]
Ending balance, loans collectively evaluated for impairment	222,075		212,188		222,075		212,188
Total Loans	$ 228,483		$ 244,063		$ 228,483		$ 244,063

[1] Refer to Note 4 for additional information regarding impaired loans.