Allowance for Loan and Lease Losses - Roll Forward of Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 45,034	$ 50,211
Provision/ (Reversals)	1,375	(841)
Net(Charge-offs)/ Recoveries	(1,146)	(1,145)
Balance, end of period	45,263	48,225
Total commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	15,978	15,557
Provision/ (Reversals)	345	(14)
Net(Charge-offs)/ Recoveries	11	165
Balance, end of period	16,334	15,708
Total commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	11,132	12,006
Provision/ (Reversals)	727	(199)
Net(Charge-offs)/ Recoveries	(43)	(15)
Balance, end of period	11,816	11,792
Total consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	17,661	22,388
Provision/ (Reversals)	(67)	(915)
Net(Charge-offs)/ Recoveries	(783)	(1,012)
Balance, end of period	16,811	20,461
Other
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	263	260
Provision/ (Reversals)	370	287
Net(Charge-offs)/ Recoveries	(331)	(283)
Balance, end of period	302	264
Non-owner occupied commercial real estate | Total commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,598	2,022
Provision/ (Reversals)	66	(135)
Net(Charge-offs)/ Recoveries	7	3
Balance, end of period	1,671	1,890
Other commercial construction and land | Total commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	12,919	12,181
Provision/ (Reversals)	274	233
Net(Charge-offs)/ Recoveries	3	161
Balance, end of period	13,196	12,575
Multifamily commercial real estate | Total commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	186	252
Provision/ (Reversals)	(4)	(29)
Net(Charge-offs)/ Recoveries	0	0
Balance, end of period	182	223
1-4 family residential construction and land | Total commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,275	1,102
Provision/ (Reversals)	9	(83)
Net(Charge-offs)/ Recoveries	1	1
Balance, end of period	1,285	1,020
Owner occupied commercial real estate | Total commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,505	2,504
Provision/ (Reversals)	262	183
Net(Charge-offs)/ Recoveries	(80)	(112)
Balance, end of period	1,687	2,575
Commercial and industrial loans | Total commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	9,627	9,502
Provision/ (Reversals)	465	(382)
Net(Charge-offs)/ Recoveries	37	97
Balance, end of period	10,129	9,217
Lease financing | Total commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	0	0
Provision/ (Reversals)	0	0
Net(Charge-offs)/ Recoveries	0	0
Balance, end of period	0	0
1-4 family residential | Total consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	11,057	15,451
Provision/ (Reversals)	(688)	(1,710)
Net(Charge-offs)/ Recoveries	5	(211)
Balance, end of period	10,374	13,530
Home equity loans | Total consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,853	2,815
Provision/ (Reversals)	(370)	42
Net(Charge-offs)/ Recoveries	112	(68)
Balance, end of period	1,595	2,789
Other consumer loans | Total consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	4,751	4,122
Provision/ (Reversals)	991	753
Net(Charge-offs)/ Recoveries	(900)	(733)
Balance, end of period	$ 4,842	$ 4,142