Loans Receivable and Allowance for Loan Losses (Summary of Impaired Loans Receivable by Class) (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 51,548	$ 57,962
Recorded Investment	44,415	50,867
Average Recorded Investment	45,476	51,225
Interest Income Recognized	887	1,949
Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	25,764	27,141
Recorded Investment	22,095	23,152
Related Allowance	1,800	1,901
Average Recorded Investment	22,664	23,579
Interest Income Recognized	718	956
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	4,145	1,240
Recorded Investment	4,082	1,240
Related Allowance	163	185
Average Recorded Investment	4,104	1,361
Interest Income Recognized	72	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	2,513	1,170
Interest Income Recognized	0	16
Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	32,462	30,739
Recorded Investment	28,694	26,743
Related Allowance	1,963	2,086
Average Recorded Investment	29,281	26,110
Interest Income Recognized	790	1,035
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,319	24,366
Recorded Investment	13,472	21,756
Related Allowance	81	91
Average Recorded Investment	13,891	22,682
Interest Income Recognized	4	799
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,767	2,857
Recorded Investment	2,249	2,368
Related Allowance	83	94
Average Recorded Investment	2,304	2,433
Interest Income Recognized	93	115
Loans With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	34,926	39,816
Impaired financing receivable with no related allowance	28,480
Related Allowance	0	0
Average Recorded Investment	29,268	33,245
Interest Income Recognized	419	1,262
Loans With No Related Allowance [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	11,574	12,144
Recorded Investment	8,580	8,799
Related Allowance	0	0
Average Recorded Investment	8,905	9,079
Interest Income Recognized	340	451
Loans With No Related Allowance [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	3,051	0
Recorded Investment	2,989	0
Related Allowance	0	0
Average Recorded Investment	3,002	0
Interest Income Recognized	31	0
Loans With No Related Allowance [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 No Related Allowance [Member] | 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	2,513	1,170
Interest Income Recognized	0	16
Loans With No Related Allowance [Member] | Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	17,178	14,502
Recorded Investment	14,086	11,150
Related Allowance	0	0
Average Recorded Investment	14,420	10,249
Interest Income Recognized	371	467
Loans With No Related Allowance [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,238	23,754
Recorded Investment	13,391	21,144
Related Allowance	0	0
Average Recorded Investment	13,810	21,875
Interest Income Recognized	4	747
Loans With No Related Allowance [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,510	1,560
Recorded Investment	1,003	1,082
Related Allowance	0	0
Average Recorded Investment	1,038	1,121
Interest Income Recognized	44	48
Loans With Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,622	18,146
Recorded Investment	15,935	17,491
Related Allowance	2,127	2,271
Average Recorded Investment	16,208	17,980
Interest Income Recognized	468	687
Loans With Allowance Recorded [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	14,190	14,997
Recorded Investment	13,515	14,353
Related Allowance	1,800	1,901
Average Recorded Investment	13,759	14,500
Interest Income Recognized	378	505
Loans With Allowance Recorded [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,094	1,240
Recorded Investment	1,093	1,240
Related Allowance	163	185
Average Recorded Investment	1,102	1,361
Interest Income Recognized	41	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	15,284	16,237
Recorded Investment	14,608	15,593
Related Allowance	1,963	2,086
Average Recorded Investment	14,861	15,861
Interest Income Recognized	419	568
Loans With Allowance Recorded [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	81	612
Recorded Investment	81	612
Related Allowance	81	91
Average Recorded Investment	81	807
Interest Income Recognized	0	52
Loans With Allowance Recorded [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,257	1,297
Recorded Investment	1,246	1,286
Related Allowance	83	94
Average Recorded Investment	1,266	1,312
Interest Income Recognized	$ 49	$ 67