Loans Receivable and Allowance for Loan Losses - Summary of Recorded Investment Net Charge-Offs, Unpaid Principal Balance and Related Allowance for Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, Total	$ 69,127		$ 69,127		$ 44,608
Unpaid Principal Balance
Unpaid Principal Balance, Total	70,343		70,343		45,929
Related Allowance	3,404		3,404		2,273
Average Recorded Investment
Average Recorded Investment, Total	63,525	$ 47,407	56,934	$ 43,912
Interest Income Recognized
Interest Income Recognized, Total	861	596	2,002	2,117
Multi-family
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	4,159		4,159		661
Recorded Investment Net of Charge Offs, With an allowance recorded	379		379
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	4,159		4,159		661
Unpaid Principal Balance, With an allowance recorded	379		379
Related Allowance	195		195
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	2,080	203	1,205	101
Average Recorded Investment, With an allowance recorded	383		290
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	38	5	38	5
Interest Income Recognized, With an allowance recorded	5		15
Commercial and industrial
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	22,885		22,885		12,056
Recorded Investment Net of Charge Offs, With an allowance recorded	7,390		7,390		5,565
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	23,919		23,919		13,028
Unpaid Principal Balance, With an allowance recorded	7,390		7,390		5,914
Related Allowance	3,119		3,119		1,990
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	21,859	7,597	18,681	9,179
Average Recorded Investment, With an allowance recorded	7,561	12,640	7,256	8,420
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	406	102	879	500
Interest Income Recognized, With an allowance recorded	43	26	155	332
Commercial real estate - owner occupied
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	10,523		10,523		8,317
Recorded Investment Net of Charge Offs, With an allowance recorded	0		0		12
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	10,523		10,523		8,317
Unpaid Principal Balance, With an allowance recorded	0		0		12
Related Allowance	0		0		1
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	10,182	6,431	9,651	7,617
Average Recorded Investment, With an allowance recorded	0	13	6	200
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	201	103	403	288
Interest Income Recognized, With an allowance recorded	0	66	0	66
Commercial real estate - non-owner occupied
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	10,539		10,539		4,276
Recorded Investment Net of Charge Offs, With an allowance recorded	120		120		555
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	10,678		10,678		4,276
Unpaid Principal Balance, With an allowance recorded	120		120		555
Related Allowance	27		27		148
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	7,983	7,803	6,081	6,937
Average Recorded Investment, With an allowance recorded	328	664	438	821
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	118	137	133	514
Interest Income Recognized, With an allowance recorded	2	4	6	9
Construction
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded					0
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded					0
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded		335		1,330
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded		0		0
Other
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	42		42		48
Recorded Investment Net of Charge Offs, With an allowance recorded	0		0		92
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	42		42		48
Unpaid Principal Balance, With an allowance recorded	0		0		92
Related Allowance	0		0		50
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	43	49	45	35
Average Recorded Investment, With an allowance recorded	0	93	36	88
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	0	1	0	1
Interest Income Recognized, With an allowance recorded	0	0	0	0
Residential real estate
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	3,799		3,799		4,331
Recorded Investment Net of Charge Offs, With an allowance recorded	200		200		395
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	3,842		3,842		4,331
Unpaid Principal Balance, With an allowance recorded	200		200		395
Related Allowance	63		63		84
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	3,835	4,044	4,039	3,910
Average Recorded Investment, With an allowance recorded	300	474	421	419
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	39	20	83	62
Interest Income Recognized, With an allowance recorded	0	1	0	1
Manufactured housing
Recorded Investment Net of Charge offs
Recorded Investment Net of Charge Offs, With no related allowance recorded	9,091		9,091		8,300
Recorded Investment Net of Charge Offs, With an allowance recorded	0		0
Unpaid Principal Balance
Unpaid Principal Balance, With no related allowance recorded	9,091		9,091		$ 8,300
Unpaid Principal Balance, With an allowance recorded	0		0
Related Allowance	0		0
Average Recorded Investment
Average Recorded Investment, With no related allowance recorded	8,971	7,061	8,785	4,855
Average Recorded Investment, With an allowance recorded	0		0
Interest Income Recognized
Interest Income Recognized, With no related allowance recorded	9	$ 131	290	$ 339
Interest Income Recognized, With an allowance recorded	$ 0		$ 0