Loans Receivable, Net - Aging of Recorded Investment in Past Due Loans Excluding PCI Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 40,673	$ 36,165
Greater than 90 Days Past Due	14,507	10,917
Loans Not Past Due	3,857,944	3,785,721
Total loans	3,898,617	3,821,886
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14,020	20,561
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,146	4,687
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	17,385	19,729
Greater than 90 Days Past Due	6,730	7,159
Loans Not Past Due	1,726,816	1,692,744
Total loans	1,744,201	1,712,473
Residential Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,685	9,532
Residential Real Estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,970	3,038
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,429	5,884
Greater than 90 Days Past Due	849	890
Loans Not Past Due	549,751	528,330
Total loans	556,180	534,214
Commercial Real Estate - Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	682	3,962
Commercial Real Estate - Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,898	1,032
Commercial Real Estate - Investor
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,760	521
Greater than 90 Days Past Due	5,522	521
Loans Not Past Due	1,108,182	1,131,554
Total loans	1,120,942	1,132,075
Commercial Real Estate - Investor | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,732	0
Commercial Real Estate - Investor | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,506	0
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,431	3,918
Greater than 90 Days Past Due	1,178	1,963
Loans Not Past Due	280,238	286,637
Total loans	283,669	290,555
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,756	1,519
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	497	436
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	668	6,113
Greater than 90 Days Past Due	228	384
Loans Not Past Due	192,957	146,456
Total loans	193,625	152,569
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	165	5,548
Commercial and Industrial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 275	$ 181