Loans Receivable, Net - Aging of Recorded Investment in Past Due Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$ 6,434	$ 8,329
60-89 Days Past Due	2,169	1,927
Greater than 90 Days Past Due	19,528	16,767
Total Past Due	28,131	27,023
Loans Not Past Due	1,774,125	1,691,664
Total loans	1,802,256	1,718,687
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	4,797	7,365
60-89 Days Past Due	1,846	1,695
Greater than 90 Days Past Due	3,204	1,619
Total Past Due	9,847	10,679
Loans Not Past Due	790,543	774,762
Total loans	800,390	785,441
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,374	119
Greater than 90 Days Past Due	14,601	12,758
Total Past Due	15,975	12,877
Loans Not Past Due	682,311	637,074
Total loans	698,286	649,951
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	263	845
60-89 Days Past Due	323	232
Greater than 90 Days Past Due	1,608	1,833
Total Past Due	2,194	2,910
Loans Not Past Due	190,157	196,439
Total loans	192,351	199,349
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days Past Due	115	557
Total Past Due	115	557
Loans Not Past Due	111,114	83,389
Total loans	$ 111,229	$ 83,946