Loans Receivable, Net - Aging of Recorded Investment in Past Due Loans Excluding PCI Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	$ 13,091	$ 15,109
Total Past Due	21,433	25,189
Loans Not Past Due	2,003,178	1,972,749
Total loans	2,024,611	1,997,938
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,048	6,041
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,294	4,039
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	5,890	3,168
Total Past Due	12,049	9,959
Loans Not Past Due	834,963	832,047
Total loans	847,012	842,006
Residential Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,933	4,075
Residential Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,226	2,716
Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	4,759	7,684
Total Past Due	4,994	7,764
Loans Not Past Due	303,672	299,745
Total loans	308,666	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	235	80
Commercial Real Estate - Investor [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	1,189	2,649
Total Past Due	2,030	4,074
Loans Not Past Due	534,517	506,651
Total loans	536,547	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	841	1,208
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	1,008	1,248
Total Past Due	2,105	3,024
Loans Not Past Due	189,086	190,136
Total loans	191,191	193,160
Consumer [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	880	1,661
Consumer [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	217	115
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	245	360
Total Past Due	255	368
Loans Not Past Due	140,940	144,170
Total loans	141,195	144,538
Commercial and Industrial [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 8
Commercial and Industrial [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 10