Loans Receivable, Net - Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method Excluding PCI Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Allowance for loan losses:
Balance at beginning of period	$ 15,183	$ 16,722
Provision (benefit) charged to operations	700	563
Charge-offs	(205)	(1,172)
Recoveries	473	101
Balance at end of period	16,151	16,214
Ending allowance balance attributed to loans:
Individually evaluated for impairment	976		$ 510
Collectively evaluated for impairment	15,175		14,673
Total ending allowance balance	16,151		15,183
Loans:
Loans individually evaluated for impairment	35,343		31,042
Loans collectively evaluated for impairment	3,813,580		3,790,844
Total loans	3,848,923		3,821,886
Residential Real Estate
Allowance for loan losses:
Balance at beginning of period	2,245	6,590
Provision (benefit) charged to operations	(627)	(11)
Charge-offs	(49)	(78)
Recoveries	0	54
Balance at end of period	1,569	6,555
Ending allowance balance attributed to loans:
Individually evaluated for impairment	285		266
Collectively evaluated for impairment	1,284		1,979
Total ending allowance balance	1,569		2,245
Loans:
Loans individually evaluated for impairment	13,072		13,306
Loans collectively evaluated for impairment	1,700,410		1,699,167
Total loans	1,713,482		1,712,473
Commercial Real Estate - Owner Occupied
Allowance for loan losses:
Balance at beginning of period	2,999	2,292
Provision (benefit) charged to operations	390	1,039
Charge-offs	(50)	(968)
Recoveries	110
Balance at end of period	3,449	2,363
Ending allowance balance attributed to loans:
Individually evaluated for impairment			0
Collectively evaluated for impairment	3,449		2,999
Total ending allowance balance	3,449		2,999
Loans:
Loans individually evaluated for impairment	10,763		11,123
Loans collectively evaluated for impairment	520,562		523,091
Total loans	531,325		534,214
Commercial Real Estate - Investor
Allowance for loan losses:
Balance at beginning of period	6,361	4,873
Provision (benefit) charged to operations	993	(581)
Charge-offs	0	0
Recoveries	7	10
Balance at end of period	7,361	4,302
Ending allowance balance attributed to loans:
Individually evaluated for impairment	606		119
Collectively evaluated for impairment	6,755		6,242
Total ending allowance balance	7,361		6,361
Loans:
Loans individually evaluated for impairment	8,718		3,789
Loans collectively evaluated for impairment	1,103,271		1,128,286
Total loans	1,111,989		1,132,075
Consumer
Allowance for loan losses:
Balance at beginning of period	1,110	1,095
Provision (benefit) charged to operations	20	(40)
Charge-offs	(18)	(3)
Recoveries	24	29
Balance at end of period	1,136	1,081
Ending allowance balance attributed to loans:
Individually evaluated for impairment	85		125
Collectively evaluated for impairment	1,051		985
Total ending allowance balance	1,136		1,110
Loans:
Loans individually evaluated for impairment	2,522		2,556
Loans collectively evaluated for impairment	284,015		287,999
Total loans	286,537		290,555
Commercial and Industrial
Allowance for loan losses:
Balance at beginning of period	2,037	1,639
Provision (benefit) charged to operations	(201)	(144)
Charge-offs	(88)	(123)
Recoveries	332	8
Balance at end of period	2,080	1,380
Ending allowance balance attributed to loans:
Individually evaluated for impairment			0
Collectively evaluated for impairment	2,080		2,037
Total ending allowance balance	2,080		2,037
Loans:
Loans individually evaluated for impairment	268		268
Loans collectively evaluated for impairment	205,322		152,301
Total loans	205,590		152,569
Unallocated
Allowance for loan losses:
Balance at beginning of period	431	233
Provision (benefit) charged to operations	125	300
Balance at end of period	556	$ 533
Ending allowance balance attributed to loans:
Collectively evaluated for impairment	556		431
Total ending allowance balance	556		431
Loans:
Total loans	$ 0		$ 0