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, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 75,785	$ 94,514
Recorded Investment	67,889	85,395
Average balance of impaired loans	71,143
Average Recorded Investment		87,869
Interest Income Recognized	1,917	2,328
Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	27,326	30,465
Recorded Investment	23,396	25,535
Related Allowance	1,959	2,367
Average Recorded Investment	23,507	26,244
Interest Income Recognized	728	912
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	23,772	42,526
Recorded Investment	23,317	41,014
Related Allowance	225	2,329
Average Recorded Investment	24,080	41,387
Interest Income Recognized	719	914
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	2,096	0
Recorded Investment	2,096	0
Related Allowance	0	0
Average Recorded Investment	798	0
Interest Income Recognized	15	0
Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	53,194	72,991
Recorded Investment	48,809	66,549
Related Allowance	2,184	4,696
Average Recorded Investment	48,385	67,631
Interest Income Recognized	1,462	1,826
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	19,707	18,708
Recorded Investment	16,678	16,462
Related Allowance	91	2,318
Average Recorded Investment	20,309	17,790
Interest Income Recognized	362	394
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,884	2,815
Recorded Investment	2,402	2,384
Related Allowance	106	113
Average Recorded Investment	2,449	2,448
Interest Income Recognized	93	108
Loans With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	54,708	23,881
Average Recorded Investment	48,366	18,544
Interest Income Recognized	1,296	389
Loans With No Related Allowance [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	12,066	14,942
Recorded Investment	8,782	10,629
Average Recorded Investment	9,018	11,138
Interest Income Recognized	353	357
Loans With No Related Allowance [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	22,517	4,971
Recorded Investment	22,062	4,708
Average Recorded Investment	22,681	4,713
Interest Income Recognized	670	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	2,096	0
Recorded Investment	2,096	0
Average Recorded Investment	798	0
Interest Income Recognized	15	0
Loans With No Related Allowance [Member] | Mortgage Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	36,679	19,913
Recorded Investment	32,940	15,337
Average Recorded Investment	32,497	15,851
Interest Income Recognized	1,038	357
Loans With No Related Allowance [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,672	2,718
Recorded Investment	14,666	2,179
Average Recorded Investment	14,955	1,823
Interest Income Recognized	221	4
Loans With No Related Allowance [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,357	1,250
Recorded Investment	885	830
Average Recorded Investment	914	870
Interest Income Recognized	37	28
Loans With Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	21,077	70,633
Recorded Investment	19,398	67,049
Related Allowance	2,381	7,127
Average Recorded Investment	22,777	69,325
Interest Income Recognized	621	1,939
Loans With Allowance Recorded [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	15,260	15,523
Recorded Investment	14,614	14,906
Related Allowance	1,959	2,367
Average Recorded Investment	14,489	15,106
Interest Income Recognized	375	555
Loans With Allowance Recorded [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,255	37,555
Recorded Investment	1,255	36,306
Related Allowance	225	2,329
Average Recorded Investment	1,399	36,674
Interest Income Recognized	49	914
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	16,515	53,078
Recorded Investment	15,869	51,212
Related Allowance	2,184	4,696
Average Recorded Investment	15,888	51,780
Interest Income Recognized	424	1,469
Loans With Allowance Recorded [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	3,035	15,990
Recorded Investment	2,012	14,283
Related Allowance	91	2,318
Average Recorded Investment	5,354	15,967
Interest Income Recognized	141	390
Loans With Allowance Recorded [Member] | Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,527	1,565
Recorded Investment	1,517	1,554
Related Allowance	106	113
Average Recorded Investment	1,535	1,578
Interest Income Recognized	$ 56	$ 80