Loans Receivable and Allowance for Loan Losses (Details 7) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Loans individually evaluated for impairment	$ 251,074		$ 384,522
Loans collectively evaluated for impairment	11,758,885		12,001,856
Total loans	12,009,959		12,386,378
Loans individually evaluated for impairment, allowance for loan losses	19,568		21,531
Loans collectively evaluated for impairment, allowance for loan losses	99,032		117,469
Total allowance for loan losses	118,600	134,000	139,000	143,900	144,250	145,501
Consumer and Other Loans
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Loans individually evaluated for impairment	5,323
Loans collectively evaluated for impairment	233,906		239,681
Total loans	239,229		239,681
Loans individually evaluated for impairment, allowance for loan losses	3,882
Loans collectively evaluated for impairment, allowance for loan losses	5,658		8,824
Total allowance for loan losses	9,540	10,007	8,824	7,605	6,357	6,316
Mortgage Loans (Gross)
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Total loans	11,770,730		12,146,697
Mortgage Loans (Gross) | Residential
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Loans individually evaluated for impairment	177,038		311,930
Loans collectively evaluated for impairment	7,147,636		7,725,346
Total loans	7,324,674		8,037,276
Loans individually evaluated for impairment, allowance for loan losses	7,853		18,352
Loans collectively evaluated for impairment, allowance for loan losses	48,699		61,985
Total allowance for loan losses	56,552	74,717	80,337	78,788	91,546	89,267
Mortgage Loans (Gross) | Multi-Family
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Loans individually evaluated for impairment	48,551		52,538
Loans collectively evaluated for impairment	3,535,057		3,243,917
Total loans	3,583,608		3,296,455
Loans individually evaluated for impairment, allowance for loan losses	5,234		2,877
Loans collectively evaluated for impairment, allowance for loan losses	31,841		33,826
Total allowance for loan losses	37,075	34,578	36,703	40,865	33,952	35,514
Mortgage Loans (Gross) | Commercial Real Estate
Balances of our loans receivable and the related allowance for loan loss allocation by segment and by the impairment methodology followed in determining the allowance for loan losses
Loans individually evaluated for impairment	20,162		20,054
Loans collectively evaluated for impairment	842,286		792,912
Total loans	862,448		812,966
Loans individually evaluated for impairment, allowance for loan losses	2,599		302
Loans collectively evaluated for impairment, allowance for loan losses	12,834		12,834
Total allowance for loan losses	$ 15,433	$ 14,698	$ 13,136	$ 16,642	$ 12,395	$ 14,404