Loans Receivable and Allowance for Loan Losses (Summary of Allowance for Loan Losses by Portfolio Segment and Impairment Classification) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 6,653	$ 7,127
Collectively evaluated for impairment	54,457	54,607
Total	61,110	61,734	63,420	64,664
Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	4,896	4,696
Collectively evaluated for impairment	27,990	27,281
Total	32,886	31,977	31,470	34,144
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	1,648	2,318
Collectively evaluated for impairment	22,049	22,063
Total	23,697	24,381	25,161	24,107
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	109	113
Collectively evaluated for impairment	4,168	4,768
Total	4,277	4,881	4,379	4,929
Total Portfolio Segments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	6,653	7,127
Collectively evaluated for impairment	54,207	54,112
Total	60,860	61,239	61,010	63,180
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	250	495
Total	$ 250	$ 495	$ 2,410	$ 1,484