Loans (Activity in Allowance for Loan Losses by Portfolio Segment) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 104,453	$ 110,147	$ 126,316
Provision for loan losses	20,582	10,080	27,445
Charge-offs	(44,797)	(33,040)	(56,685)
Recoveries	12,200	17,266	13,071
Net charge-offs	(32,597)	(15,774)	(43,614)
Ending balance	92,438	104,453	110,147
Loans individually evaluated for impairment	20,596	17,537	19,549
Loans collectively evaluated for impairment	71,842	86,916	90,598
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	54,164	42,774	57,789
Provision for loan losses	27,970	25,013	14,137
Charge-offs	(32,932)	(18,493)	(33,678)
Recoveries	3,588	4,870	4,526
Net charge-offs	(29,344)	(13,623)	(29,152)
Ending balance	52,790	54,164	42,774
Loans individually evaluated for impairment	16,682	13,171	15,829
Loans collectively evaluated for impairment	36,108	40,993	26,945
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	29,346	20,912	28,534
Provision for loan losses	(6,631)	7,658	1,812
Charge-offs	(1,329)	(3,951)	(10,776)
Recoveries	1,204	4,727	1,342
Net charge-offs	(125)	776	(9,434)
Ending balance	22,590	29,346	20,912
Loans individually evaluated for impairment	3,914	4,366	3,625
Loans collectively evaluated for impairment	18,676	24,980	17,287
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	5,252	3,540	3,223
Provision for loan losses	697	2,350	2,610
Charge-offs	(1,047)	(1,495)	(2,789)
Recoveries	328	857	496
Net charge-offs	(719)	(638)	(2,293)
Ending balance	5,230	5,252	3,540
Loans individually evaluated for impairment	0	0	95
Loans collectively evaluated for impairment	5,230	5,252	3,445
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	3,507	12,635	11,974
Provision for loan losses	3,912	(6,839)	3,396
Charge-offs	(9,489)	(9,101)	(9,442)
Recoveries	7,080	6,812	6,707
Net charge-offs	(2,409)	(2,289)	(2,735)
Ending balance	5,010	3,507	12,635
Loans individually evaluated for impairment	0	0	0
Loans collectively evaluated for impairment	5,010	3,507	12,635
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	12,184	30,286	24,796
Provision for loan losses	(5,366)	(18,102)	5,490
Charge-offs	0	0	0
Recoveries	0	0	0
Net charge-offs	0	0	0
Ending balance	6,818	12,184	30,286
Loans individually evaluated for impairment	0	0	0
Loans collectively evaluated for impairment	$ 6,818	$ 12,184	$ 30,286