Loans Receivable and Allowance for Loan Losses (Summary of Impaired Loans Receivable by Class) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 61,446	$ 57,962
Recorded Investment	54,193	50,867
Average Recorded Investment	54,500	51,225
Interest Income Recognized	320	1,949
Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	26,935	27,141
Recorded Investment	22,947	23,152
Related Allowance	1,989	1,901
Average Recorded Investment	23,013	23,579
Interest Income Recognized	253	956
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,224	1,240
Recorded Investment	1,224	1,240
Related Allowance	178	185
Average Recorded Investment	1,232	1,361
Interest Income Recognized	15	63
Multi-Family [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Related Allowance	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,553	2,358
Recorded Investment	2,517	2,351
Related Allowance	0	0
Average Recorded Investment	2,505	1,170
Interest Income Recognized	0	16
Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	30,712	30,739
Recorded Investment	26,688	26,743
Related Allowance	2,167	2,086
Average Recorded Investment	26,750	26,110
Interest Income Recognized	268	1,035
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	27,907	24,366
Recorded Investment	25,186	21,756
Related Allowance	2,796	91
Average Recorded Investment	25,442	22,682
Interest Income Recognized	12	799
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,827	2,857
Recorded Investment	2,319	2,368
Related Allowance	90	94
Average Recorded Investment	2,345	2,433
Interest Income Recognized	40	115
Loans With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	30,340	39,816
Impaired financing receivable with no related allowance	26,300
Average Recorded Investment	26,391	33,245
Interest Income Recognized	130	1,262
Loans With No Related Allowance [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	11,046	12,144
Recorded Investment	8,121	8,799
Average Recorded Investment	8,148	9,079
Interest Income Recognized	106	451
Loans With No Related Allowance [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Loans With No Related Allowance [Member] | Multi-Family [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Loans With No Related Allowance [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,553	2,358
Recorded Investment	2,517	2,351
Average Recorded Investment	2,505	1,170
Interest Income Recognized	0	16
Loans With No Related Allowance [Member] | Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	13,599	14,502
Recorded Investment	10,638	11,150
Average Recorded Investment	10,653	10,249
Interest Income Recognized	106	467
Loans With No Related Allowance [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	15,198	23,754
Recorded Investment	14,570	21,144
Average Recorded Investment	14,672	21,875
Interest Income Recognized	0	747
Loans With No Related Allowance [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,543	1,560
Recorded Investment	1,046	1,082
Average Recorded Investment	1,066	1,121
Interest Income Recognized	24	48
Loans With Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	31,106	18,146
Recorded Investment	27,939	17,491
Related Allowance	5,053	2,271
Average Recorded Investment	28,146	17,980
Interest Income Recognized	190	687
Loans With Allowance Recorded [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	15,889	14,997
Recorded Investment	14,826	14,353
Related Allowance	1,989	1,901
Average Recorded Investment	14,865	14,500
Interest Income Recognized	147	505
Loans With Allowance Recorded [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,224	1,240
Recorded Investment	1,224	1,240
Related Allowance	178	185
Average Recorded Investment	1,232	1,361
Interest Income Recognized	15	63
Loans With Allowance Recorded [Member] | Multi-Family [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Related Allowance	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Loans With Allowance Recorded [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Related Allowance	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Loans With Allowance Recorded [Member] | Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	17,113	16,237
Recorded Investment	16,050	15,593
Related Allowance	2,167	2,086
Average Recorded Investment	16,097	15,861
Interest Income Recognized	162	568
Loans With Allowance Recorded [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	12,709	612
Recorded Investment	10,616	612
Related Allowance	2,796	91
Average Recorded Investment	10,770	807
Interest Income Recognized	12	52
Loans With Allowance Recorded [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,284	1,297
Recorded Investment	1,273	1,286
Related Allowance	90	94
Average Recorded Investment	1,279	1,312
Interest Income Recognized	$ 16	$ 67