Loans Receivable and Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Loans receivable and allowance for loan losses
30-59 Days Past Due	$ 143,684	$ 146,782
60-89 Days Past Due	40,145	37,637
90 Days or More	287,310	301,407
Total Past Due	471,139	485,826
Current	12,376,566	12,670,088
Total loans	12,847,705	13,155,914
Net unamortized premiums and deferred loan origination costs	64,078	68,058
Loans receivable	12,911,783	13,223,972
Allowance for loan losses	(144,250)	(145,501)	(149,899)	(157,185)
Loans receivable, net	12,767,533	13,078,471
Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	133,826	144,932
60-89 Days Past Due	37,350	36,947
90 Days or More	609	328
Total Past Due	171,785	182,207
Current	12,310,072	12,658,949
Total loans	12,481,857	12,841,156
Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	9,858	1,850
60-89 Days Past Due	2,795	690
90 Days or More	286,701	301,079
Total Past Due	299,354	303,619
Current	66,494	11,139
Total loans	365,848	314,758
Consumer and Other Loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,896	3,223
60-89 Days Past Due	1,527	1,315
90 Days or More	6,246	6,508
Total Past Due	10,669	11,046
Current	248,336	253,048
Total loans	259,005	264,094
Allowance for loan losses	(6,357)	(6,316)	(3,672)	(3,800)
Consumer and Other Loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,896	3,223
60-89 Days Past Due	1,527	1,315
Total Past Due	4,423	4,538
Current	248,084	253,048
Total loans	252,507	257,586
Consumer and Other Loans | Non-accrual loans
Loans receivable and allowance for loan losses
90 Days or More	6,246	6,508
Total Past Due	6,246	6,508
Current	252
Total loans	6,498	6,508
Consumer and Other Loans | Home equity lines of credit
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,828	3,103
60-89 Days Past Due	1,350	1,092
90 Days or More	6,178	6,459
Total Past Due	10,356	10,654
Current	213,205	221,266
Total loans	223,561	231,920
Consumer and Other Loans | Home equity lines of credit | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,828	3,103
60-89 Days Past Due	1,350	1,092
Total Past Due	4,178	4,195
Current	212,953	221,266
Total loans	217,131	225,461
Consumer and Other Loans | Home equity lines of credit | Non-accrual loans
Loans receivable and allowance for loan losses
90 Days or More	6,178	6,459
Total Past Due	6,178	6,459
Current	252
Total loans	6,430	6,459
Consumer and Other Loans | Other Loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	68	120
60-89 Days Past Due	177	223
90 Days or More	68	49
Total Past Due	313	392
Current	35,131	31,782
Total loans	35,444	32,174
Consumer and Other Loans | Other Loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	68	120
60-89 Days Past Due	177	223
Total Past Due	245	343
Current	35,131	31,782
Total loans	35,376	32,125
Consumer and Other Loans | Other Loans | Non-accrual loans
Loans receivable and allowance for loan losses
90 Days or More	68	49
Total Past Due	68	49
Total loans	68	49
Mortgage Loans (Gross)
Loans receivable and allowance for loan losses
30-59 Days Past Due	140,788	143,559
60-89 Days Past Due	38,618	36,322
90 Days or More	281,064	294,899
Total Past Due	460,470	474,780
Current	12,128,230	12,417,040
Total loans	12,588,700	12,891,820
Mortgage Loans (Gross) | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	130,930	141,709
60-89 Days Past Due	35,823	35,632
90 Days or More	609	328
Total Past Due	167,362	177,669
Current	12,061,988	12,405,901
Total loans	12,229,350	12,583,570
Mortgage Loans (Gross) | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	9,858	1,850
60-89 Days Past Due	2,795	690
90 Days or More	280,455	294,571
Total Past Due	293,108	297,111
Current	66,242	11,139
Total loans	359,350	308,250
Mortgage Loans (Gross) | Residential
Loans receivable and allowance for loan losses
30-59 Days Past Due	119,088	108,280
60-89 Days Past Due	26,299	27,814
90 Days or More	271,143	280,671
Total Past Due	416,530	416,765
Current	8,780,783	9,294,461
Total loans	9,197,313	9,711,226
Allowance for loan losses	(91,546)	(89,267)	(90,898)	(105,991)
Mortgage Loans (Gross) | Residential | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	110,593	106,430
60-89 Days Past Due	23,504	27,124
Total Past Due	134,097	133,554
Current	8,719,740	9,286,621
Total loans	8,853,837	9,420,175
Mortgage Loans (Gross) | Residential | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	8,495	1,850
60-89 Days Past Due	2,795	690
90 Days or More	271,143	280,671
Total Past Due	282,433	283,211
Current	61,043	7,840
Total loans	343,476	291,051
Mortgage Loans (Gross) | Residential | Full documentation interest-only loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	32,932	30,520
60-89 Days Past Due	9,194	9,650
90 Days or More	92,128	97,907
Total Past Due	134,254	138,077
Current	1,755,229	1,863,319
Total loans	1,889,483	2,001,396
Mortgage Loans (Gross) | Residential | Full documentation interest-only loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	31,298	30,520
60-89 Days Past Due	8,343	8,973
Total Past Due	39,641	39,493
Current	1,732,224	1,862,382
Total loans	1,771,865	1,901,875
Mortgage Loans (Gross) | Residential | Full documentation interest-only loans | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	1,634
60-89 Days Past Due	851	677
90 Days or More	92,128	97,907
Total Past Due	94,613	98,584
Current	23,005	937
Total loans	117,618	99,521
Mortgage Loans (Gross) | Residential | Full documentation amortizing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	39,849	36,281
60-89 Days Past Due	6,032	6,564
90 Days or More	43,320	43,014
Total Past Due	89,201	85,859
Current	5,847,778	6,219,013
Total loans	5,936,979	6,304,872
Mortgage Loans (Gross) | Residential | Full documentation amortizing loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	39,310	35,918
60-89 Days Past Due	5,624	6,564
Total Past Due	44,934	42,482
Current	5,839,072	6,218,064
Total loans	5,884,006	6,260,546
Mortgage Loans (Gross) | Residential | Full documentation amortizing loans | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	539	363
60-89 Days Past Due	408
90 Days or More	43,320	43,014
Total Past Due	44,267	43,377
Current	8,706	949
Total loans	52,973	44,326
Mortgage Loans (Gross) | Residential | Reduced documentation interest-only loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	34,584	29,254
60-89 Days Past Due	9,054	7,694
90 Days or More	105,326	107,254
Total Past Due	148,964	144,202
Current	834,806	861,093
Total loans	983,770	1,005,295
Mortgage Loans (Gross) | Residential | Reduced documentation interest-only loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	30,428	28,212
60-89 Days Past Due	7,587	7,694
Total Past Due	38,015	35,906
Current	809,738	855,907
Total loans	847,753	891,813
Mortgage Loans (Gross) | Residential | Reduced documentation interest-only loans | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	4,156	1,042
60-89 Days Past Due	1,467
90 Days or More	105,326	107,254
Total Past Due	110,949	108,296
Current	25,068	5,186
Total loans	136,017	113,482
Mortgage Loans (Gross) | Residential | Reduced documentation amortizing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	11,723	12,225
60-89 Days Past Due	2,019	3,906
90 Days or More	30,369	32,496
Total Past Due	44,111	48,627
Current	342,970	351,036
Total loans	387,081	399,663
Mortgage Loans (Gross) | Residential | Reduced documentation amortizing loans | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	9,557	11,780
60-89 Days Past Due	1,950	3,893
Total Past Due	11,507	15,673
Current	338,706	350,268
Total loans	350,213	365,941
Mortgage Loans (Gross) | Residential | Reduced documentation amortizing loans | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,166	445
60-89 Days Past Due	69	13
90 Days or More	30,369	32,496
Total Past Due	32,604	32,954
Current	4,264	768
Total loans	36,868	33,722
Mortgage Loans (Gross) | Multi-Family
Loans receivable and allowance for loan losses
30-59 Days Past Due	17,450	21,743
60-89 Days Past Due	5,731	5,382
90 Days or More	3,706	7,359
Total Past Due	26,887	34,484
Current	2,549,431	2,372,194
Total loans	2,576,318	2,406,678
Allowance for loan losses	(33,952)	(35,514)	(44,927)	(35,422)
Mortgage Loans (Gross) | Multi-Family | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	17,450	21,743
60-89 Days Past Due	5,731	5,382
Total Past Due	23,181	27,125
Current	2,545,582	2,368,895
Total loans	2,568,763	2,396,020
Mortgage Loans (Gross) | Multi-Family | Non-accrual loans
Loans receivable and allowance for loan losses
90 Days or More	3,706	7,359
Total Past Due	3,706	7,359
Current	3,849	3,299
Total loans	7,555	10,658
Mortgage Loans (Gross) | Commercial Real Estate
Loans receivable and allowance for loan losses
30-59 Days Past Due	4,250	13,536
60-89 Days Past Due	6,588	3,126
90 Days or More	6,215	6,869
Total Past Due	17,053	23,531
Current	798,016	750,385
Total loans	815,069	773,916
Allowance for loan losses	(12,395)	(14,404)	(10,402)	(11,972)
Mortgage Loans (Gross) | Commercial Real Estate | Accruing loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	2,887	13,536
60-89 Days Past Due	6,588	3,126
90 Days or More	609	328
Total Past Due	10,084	16,990
Current	796,666	750,385
Total loans	806,750	767,375
Mortgage Loans (Gross) | Commercial Real Estate | Non-accrual loans
Loans receivable and allowance for loan losses
30-59 Days Past Due	1,363
90 Days or More	5,606	6,541
Total Past Due	6,969	6,541
Current	1,350
Total loans	$ 8,319	$ 6,541