Loans Receivable and Allowance for Loan Losses (Allowance for Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	$ 111,600	$ 139,000
Provision (credited) charged to operations	(343)	1,631
Charge-offs	(2,490)	(8,835)
Recoveries	1,733	2,204
Balance at the end of the period	110,500	134,000
Consumer and Other Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	8,825	8,824
Provision (credited) charged to operations	1,234	1,981
Charge-offs	(349)	(897)
Recoveries	109	99
Balance at the end of the period	9,819	10,007
Mortgage loans (gross) | Residential
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	46,283	80,337
Provision (credited) charged to operations	(1,851)	(3,476)
Charge-offs	(1,757)	(4,093)
Recoveries	806	1,949
Balance at the end of the period	43,481	74,717
Mortgage loans (gross) | Multi-family
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	39,250	36,703
Provision (credited) charged to operations	256	(1,412)
Charge-offs	(242)	(869)
Recoveries	818	156
Balance at the end of the period	40,082	34,578
Mortgage loans (gross) | Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	17,242	13,136
Provision (credited) charged to operations	18	4,538
Charge-offs	(142)	(2,976)
Recoveries		0
Balance at the end of the period	$ 17,118	$ 14,698