Loans Receivable and Allowance for Loan Losses - Schedule of Loan Portfolio Segments by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Recorded Investment
Loans receivable	$ 10,380,358	$ 11,111,727
Not criticized
Recorded Investment
Loans receivable	10,100,670	10,808,709
Special mention
Recorded Investment
Loans receivable	50,158	54,138
Substandard
Recorded Investment
Loans receivable	229,530	248,177
Doubtful
Recorded Investment
Loans receivable	0	703
Consumer and Other Loans
Recorded Investment
Loans receivable	239,114	252,693
Consumer and Other Loans | Home Equity and Other Consumer
Recorded Investment
Loans receivable	139,338	160,819
Consumer and Other Loans | Home Equity and Other Consumer | Not criticized
Recorded Investment
Loans receivable	134,305	153,911
Consumer and Other Loans | Home Equity and Other Consumer | Special mention
Recorded Investment
Loans receivable	550	502
Consumer and Other Loans | Home Equity and Other Consumer | Substandard
Recorded Investment
Loans receivable	4,483	6,406
Consumer and Other Loans | Home Equity and Other Consumer | Doubtful
Recorded Investment
Loans receivable	0	0
Consumer and Other Loans | Commercial and Industrial
Recorded Investment
Loans receivable	99,776	91,874
Consumer and Other Loans | Commercial and Industrial | Not criticized
Recorded Investment
Loans receivable	99,087	89,744
Consumer and Other Loans | Commercial and Industrial | Special mention
Recorded Investment
Loans receivable	647	1,427
Consumer and Other Loans | Commercial and Industrial | Substandard
Recorded Investment
Loans receivable	42	0
Consumer and Other Loans | Commercial and Industrial | Doubtful
Recorded Investment
Loans receivable	0	703
Mortgage Loans
Recorded Investment
Loans receivable	10,141,244	10,859,034
Mortgage Loans | Residential
Recorded Investment
Loans receivable	5,365,363	6,015,415
Mortgage Loans | Residential | Not criticized
Recorded Investment
Loans receivable	5,158,878	5,814,975
Mortgage Loans | Residential | Special mention
Recorded Investment
Loans receivable	14,922	16,837
Mortgage Loans | Residential | Substandard
Recorded Investment
Loans receivable	191,563	183,603
Mortgage Loans | Residential | Doubtful
Recorded Investment
Loans receivable	0	0
Mortgage Loans | Multi- Family
Recorded Investment
Loans receivable	4,046,622	4,024,105
Mortgage Loans | Multi- Family | Not criticized
Recorded Investment
Loans receivable	4,005,703	3,981,050
Mortgage Loans | Multi- Family | Special mention
Recorded Investment
Loans receivable	24,804	14,931
Mortgage Loans | Multi- Family | Substandard
Recorded Investment
Loans receivable	16,115	28,124
Mortgage Loans | Multi- Family | Doubtful
Recorded Investment
Loans receivable	0	0
Mortgage Loans | Commercial Real Estate
Recorded Investment
Loans receivable	729,259	819,514
Mortgage Loans | Commercial Real Estate | Not criticized
Recorded Investment
Loans receivable	702,697	769,029
Mortgage Loans | Commercial Real Estate | Special mention
Recorded Investment
Loans receivable	9,235	20,441
Mortgage Loans | Commercial Real Estate | Substandard
Recorded Investment
Loans receivable	17,327	30,044
Mortgage Loans | Commercial Real Estate | Doubtful
Recorded Investment
Loans receivable	$ 0	$ 0