Loans Receivable and Allowance for Loan Losses (Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	$ 98,000	$ 111,600
Provision charged (credited) to operations	(3,127)	(343)
Charge-offs	(2,740)	(2,490)
Recoveries	2,067	1,733
Balance at the end of the period	94,200	110,500
Consumer and Other Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	6,288	8,825
Provision charged (credited) to operations	841	1,234
Charge-offs	(765)	(349)
Recoveries	70	109
Balance at the end of the period	6,434	9,819
Mortgage Loans | Residential
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	44,951	46,283
Provision charged (credited) to operations	138	(1,851)
Charge-offs	(1,665)	(1,757)
Recoveries	954	806
Balance at the end of the period	44,378	43,481
Mortgage Loans | Multi-Family
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	35,544	39,250
Provision charged (credited) to operations	(3,257)	256
Charge-offs	(310)	(242)
Recoveries	1,043	818
Balance at the end of the period	33,020	40,082
Mortgage Loans | Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of the period	11,217	17,242
Provision charged (credited) to operations	(849)	18
Charge-offs	0	(142)
Recoveries	0	0
Balance at the end of the period	$ 10,368	$ 17,118