Loans Receivable and Allowance for Loan Losses (Average Recorded Investment, Interest Income Recognized and Cash Basis Interest Income on Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment	$ 247,622	$ 386,344
Interest income recognized	2,324	2,820
Cash basis interest income	2,363	2,919
Consumer and Other Loans | Home equity and other consumer
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	5,829	4,083
Interest income recognized, loans with an allowance recorded	6	4
Cash basis interest income, loans with an allowance recorded	16	6
Mortgage loans | Residential | Full documentation interest-only
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	44,759	108,696
Interest income recognized, loans with an allowance recorded	349	650
Cash basis interest income, loans with an allowance recorded	353	650
Mortgage loans | Residential | Full documentation amortizing loans
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	43,989	37,802
Average recorded investment, loans without an allowance recorded	0	600
Interest income recognized, loans with an allowance recorded	395	301
Interest income recognized, loans without an allowance recorded		8
Cash basis interest income, loans with an allowance recorded	386	294
Cash basis interest income, loans without an allowance recorded		8
Mortgage loans | Residential | Reduced documentation interest-only
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	76,396	137,429
Interest income recognized, loans with an allowance recorded	730	1,062
Cash basis interest income, loans with an allowance recorded	737	1,041
Mortgage loans | Residential | Reduced documentation amortizing
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	18,948	25,503
Interest income recognized, loans with an allowance recorded	162	121
Cash basis interest income, loans with an allowance recorded	162	119
Mortgage loans | Multi-family
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	24,542	28,660
Average recorded investment, loans without an allowance recorded	13,759	22,393
Interest income recognized, loans with an allowance recorded	260	358
Interest income recognized, loans without an allowance recorded	154	141
Cash basis interest income, loans with an allowance recorded	268	377
Cash basis interest income, loans without an allowance recorded	155	141
Mortgage loans | Commercial real estate
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment, loans with an allowance recorded	19,400	14,046
Average recorded investment, loans without an allowance recorded		7,132
Interest income recognized, loans with an allowance recorded	268	175
Interest income recognized, loans without an allowance recorded		0
Cash basis interest income, loans with an allowance recorded	286	283
Cash basis interest income, loans without an allowance recorded		$ 0