Loans Receivable, Net - Aging of Recorded Investment in Past Due Loans Excluding PCI Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	$ 15,026	$ 15,109
Total Past Due	24,571	25,189
Loans Not Past Due	3,024,341	1,972,749
Total loans	3,048,912	1,997,938
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,961	6,041
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,584	4,039
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	5,543	3,168
Total Past Due	12,477	9,959
Loans Not Past Due	1,095,365	832,047
Total loans	1,107,842	842,006
Residential Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,880	4,075
Residential Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,054	2,716
Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	5,213	7,684
Total Past Due	5,273	7,764
Loans Not Past Due	485,845	299,745
Total loans	491,118	307,509
Commercial Real Estate - Owner Occupied [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		80
Commercial Real Estate - Owner Occupied [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	60
Commercial Real Estate - Investor [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	1,675	2,649
Total Past Due	1,675	4,074
Loans Not Past Due	1,012,936	506,651
Total loans	1,014,611	510,725
Commercial Real Estate - Investor [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		217
Commercial Real Estate - Investor [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,208
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	1,443	1,248
Total Past Due	2,695	3,024
Loans Not Past Due	249,879	190,136
Total loans	252,574	193,160
Consumer [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	985	1,661
Consumer [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	267	115
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	1,152	360
Total Past Due	2,451	368
Loans Not Past Due	180,316	144,170
Total loans	182,767	144,538
Commercial and Industrial [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	96	$ 8
Commercial and Industrial [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,203