Loans (Impaired Loans) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	$ 61,007	$ 105,577
Recorded Investment With No Allowance	32,588	43,083
Recorded Investment With Allowance	15,874	37,314
Total Recorded Investment	48,462	80,397
Related Allowance	6,926	8,237
Average Recorded Investment	71,741	86,580
Commercial and Industrial, Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	545	1,255
Recorded Investment With No Allowance	531	0
Recorded Investment With Allowance	0	1,069
Total Recorded Investment	531	1,069
Related Allowance	0	900
Average Recorded Investment	428	214
Commercial and Industrial, Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	31,429	56,784
Recorded Investment With No Allowance	15,337	21,709
Recorded Investment With Allowance	7,004	19,096
Total Recorded Investment	22,341	40,805
Related Allowance	4,140	4,200
Average Recorded Investment	34,894	42,630
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	27,792	44,652
Recorded Investment With No Allowance	15,697	19,010
Recorded Investment With Allowance	8,870	17,149
Total Recorded Investment	24,567	36,159
Related Allowance	2,786	3,137
Average Recorded Investment	34,633	40,258
Commercial Real Estate, Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	0	1,497
Recorded Investment With No Allowance	0	1,100
Total Recorded Investment	0	1,100
Average Recorded Investment	634	1,392
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	907	961
Recorded Investment With No Allowance	745	864
Total Recorded Investment	745	864
Average Recorded Investment	804	1,617
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	334	428
Recorded Investment With No Allowance	278	400
Total Recorded Investment	278	400
Average Recorded Investment	$ 348	$ 469