Allowance for Loan and Lease Losses and Recorded Investment in Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	$ 18,805	$ 14,448
Charge-offs	(203)	(906)
Recoveries	435	305
Transfer of loans to held-for-sale	(963)
Provision	1,929	2,168
Balance at end of year	20,003	16,015
Individually evaluated for impairment	62	1,462
Collectively evaluated for impairment	19,745	14,314
Acquired with deteriorated credit quality	196	239
Total ending allowance balance	20,003	16,015
Loans:
Individually evaluated for impairment	15,264	21,909
Collectively evaluated for impairment	2,068,308	1,386,907
Acquired with deteriorated credit quality	313,423	218,456
Total ending loan balances	2,396,995	1,627,272	2,446,111
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	1,822	263
Recoveries	26
Provision	519	218
Balance at end of year	2,367	481
Collectively evaluated for impairment	2,367	481
Total ending allowance balance	2,367	481
Loans:
Collectively evaluated for impairment	297,646	74,564
Acquired with deteriorated credit quality	1,538	4,781
Total ending loan balances	299,184	79,345
Commercial Real Estate Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	5,484	3,178
Charge-offs		(105)
Recoveries	316
Provision	649	625
Balance at end of year	6,449	3,698
Individually evaluated for impairment		38
Collectively evaluated for impairment	6,449	3,636
Acquired with deteriorated credit quality		24
Total ending allowance balance	6,449	3,698
Loans:
Individually evaluated for impairment	3,218	2,511
Collectively evaluated for impairment	542,750	307,338
Acquired with deteriorated credit quality	14,613	21,616
Total ending loan balances	560,581	331,465
Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	2,566	1,478
Charge-offs		(384)
Recoveries		88
Provision	154	362
Balance at end of year	2,720	1,544
Individually evaluated for impairment	37	329
Collectively evaluated for impairment	2,683	1,215
Total ending allowance balance	2,720	1,544
Loans:
Individually evaluated for impairment	1,674	2,336
Collectively evaluated for impairment	153,708	123,329
Acquired with deteriorated credit quality		838
Total ending loan balances	155,382	126,503
SBA
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	235	118
Charge-offs	(17)	(125)
Recoveries	92	125
Provision	(99)	15
Balance at end of year	211	133
Collectively evaluated for impairment	211	133
Total ending allowance balance	211	133
Loans:
Collectively evaluated for impairment	23,064	30,329
Acquired with deteriorated credit quality	3,477	5,333
Total ending loan balances	26,541	35,662
Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	244	21
Provision	108	273
Balance at end of year	352	294
Collectively evaluated for impairment	352	294
Total ending allowance balance	352	294
Loans:
Collectively evaluated for impairment	25,144	6,831
Total ending loan balances	25,144	6,831
Lease Financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	428	261
Charge-offs		(23)
Recoveries		2
Provision	194	23
Balance at end of year	622	263
Collectively evaluated for impairment	622	263
Total ending allowance balance	622	263
Loans:
Collectively evaluated for impairment	48,537	16,418
Total ending loan balances	48,537	16,418
Real estate 1-4 family first mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	7,044	8,855
Charge-offs	(151)	(262)
Recoveries		90
Transfer of loans to held-for-sale	(963)
Provision	217	529
Balance at end of year	6,147	9,212
Individually evaluated for impairment	25	1,095
Collectively evaluated for impairment	5,926	7,902
Acquired with deteriorated credit quality	196	215
Total ending allowance balance	6,147	9,212
Loans:
Individually evaluated for impairment	10,160	17,062
Collectively evaluated for impairment	856,664	806,197
Acquired with deteriorated credit quality	292,039	185,833
Total ending loan balances	1,158,863	1,009,092
HELOC, home equity loans, and other consumer credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	532	274
Charge-offs	(35)	(7)
Recoveries	1
Provision	284	(70)
Balance at end of year	782	197
Collectively evaluated for impairment	782	197
Total ending allowance balance	782	197
Loans:
Individually evaluated for impairment	212
Collectively evaluated for impairment	120,795	21,901
Acquired with deteriorated credit quality	1,756	55
Total ending loan balances	122,763	21,956
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	450
Provision	(97)	193
Balance at end of year	353	193
Collectively evaluated for impairment	353	193
Total ending allowance balance	$ 353	$ 193