Loans Receivable and Allowance for Loan Losses - Summary of Allowance for Loan Losses by Portfolio Segment and Impairment Classification (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 2,271	$ 7,127
Collectively evaluated for impairment	59,153	54,607
Total	61,424	61,734	$ 64,664	$ 70,348
Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	2,086	4,696
Collectively evaluated for impairment	30,008	27,281
Total	32,094	31,977	34,144
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	91	2,318
Collectively evaluated for impairment	25,738	22,063
Total	25,829	24,381	24,107
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	94	113
Collectively evaluated for impairment	3,407	4,768
Total	3,501	4,881	4,929
Total Portfolio Segments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	2,271	7,127
Collectively evaluated for impairment	59,153	54,112
Total	61,424	61,239	63,180
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	0	495
Total	$ 0	$ 495	$ 1,484