Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] |
| | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Other Unobservable Inputs (Level 3) | | Total carried at fair value on a recurring basis | | | 2017 | | 2016 | | 2017 | | 2016 | | 2017 | | 2016 | | 2017 | | 2016 | | | (In thousands) | | | | | | | | | | | | | | | | | | Assets: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mortgage-backed Securities | | $ | - | | | $ | - | | | $ | 537,905 | | | $ | 516,476 | | | $ | - | | | $ | - | | | $ | 537,905 | | | $ | 516,476 | | Other securities | | | - | | | | - | | | | 338,844 | | | | 337,544 | | | | 7,394 | | | | 7,361 | | | | 346,238 | | | | 344,905 | | Interest rate swaps | | | - | | | | - | | | | 6,833 | | | | 6,350 | | | | - | | | | - | | | | 6,833 | | | | 6,350 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Total assets | | $ | - | | | $ | - | | | $ | 883,582 | | | $ | 860,370 | | | $ | 7,394 | | | $ | 7,361 | | | $ | 890,976 | | | $ | 867,731 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Liabilities: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Borrowings | | $ | - | | | $ | - | | | $ | - | | | $ | - | | | $ | 34,536 | | | $ | 33,959 | | | $ | 34,536 | | | $ | 33,959 | | Interest rate swaps | | | - | | | | - | | | | 3,040 | | | | 3,386 | | | | - | | | | - | | | | 3,040 | | | | 3,386 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Total liabilities | | $ | - | | | $ | - | | | $ | 3,040 | | | $ | 3,386 | | | $ | 34,536 | | | $ | 33,959 | | | $ | 37,576 | | | $ | 37,345 | |
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Fair Value, by Balance Sheet Grouping [Table Text Block] |
| | March 31, 2017 | | | Carrying Amount | | Fair Value | | Level 1 | | Level 2 | | Level 3 | | | (In thousands) | Assets: | | | | | | | | | | | | | | | | | | | | | | Cash and due from banks | | $ | 51,215 | | | $ | 51,215 | | | $ | 51,215 | | | $ | - | | | $ | - | | Securities held-to-maturity | | | | | | | | | | | | | | | | | | | | | Other securities | | | 36,406 | | | | 34,152 | | | | - | | | | - | | | | 34,152 | | Securities available for sale | | | | | | | | | | | | | | | | | | | | | Mortgage-backed securities | | | 537,905 | | | | 537,905 | | | | - | | | | 537,905 | | | | - | | Other securities | | | 346,238 | | | | 346,238 | | | | - | | | | 338,844 | | | | 7,394 | | Loans | | | 4,974,591 | | | | 4,956,089 | | | | - | | | | - | | | | 4,956,089 | | FHLB-NY stock | | | 57,384 | | | | 57,384 | | | | - | | | | 57,384 | | | | - | | Accrued interest receivable | | | 20,602 | | | | 20,602 | | | | - | | | | 20,602 | | | | - | | Interest rate swaps | | | 6,833 | | | | 6,833 | | | | - | | | | 6,833 | | | | - | | | | | | | | | | | | | | | | | | | | | | | Total assets | | $ | 6,031,174 | | | $ | 6,010,418 | | | $ | 51,215 | | | $ | 961,568 | | | $ | 4,997,635 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Liabilities: | | | | | | | | | | | | | | | | | | | | | Deposits | | $ | 4,410,746 | | | $ | 4,417,356 | | | $ | 2,998,927 | | | $ | 1,418,429 | | | $ | - | | Borrowings | | | 1,227,852 | | | | 1,221,367 | | | | - | | | | 1,186,831 | | | | 34,536 | | Accrued interest payable | | | 3,074 | | | | 3,074 | | | | - | | | | 3,074 | | | | - | | Interest rate swaps | | | 3,040 | | | | 3,040 | | | | - | | | | 3,040 | | | | - | | | | | | | | | | | | | | | | | | | | | | | Total liabilities | | $ | 5,644,712 | | | $ | 5,644,837 | | | $ | 2,998,927 | | | $ | 2,611,374 | | | $ | 34,536 | | | | December 31, 2016 | | | Carrying Amount | | Fair Value | | Level 1 | | Level 2 | | Level 3 | | | (In thousands) | Assets: | | | | | | | | | | | | | | | | | | | | | | Cash and due from banks | | $ | 35,857 | | | $ | 35,857 | | | $ | 35,857 | | | $ | - | | | $ | - | | Securities held-to-maturity | | | | | | | | | | | | | | | | | | | | | Other securities | | | 37,735 | | | | 35,408 | | | | - | | | | - | | | | 35,408 | | Securities available for sale | | | | | | | | | | | | | | | | | | | | | Mortgage-backed securities | | | 516,476 | | | | 516,476 | | | | - | | | | 516,476 | | | | - | | Other securities | | | 344,905 | | | | 344,905 | | | | - | | | | 337,544 | | | | 7,361 | | Loans | | | 4,835,693 | | | | 4,814,840 | | | | - | | | | - | | | | 4,814,840 | | FHLB-NY stock | | | 59,173 | | | | 59,173 | | | | - | | | | 59,173 | | | | - | | Interest rate swaps | | | 6,350 | | | | 6,350 | | | | - | | | | 6,350 | | | | - | | | | | | | | | | | | | | | | | | | | | | | Total assets | | $ | 5,836,189 | | | $ | 5,813,009 | | | $ | 35,857 | | | $ | 919,543 | | | $ | 4,857,609 | | | | | | | | | | | | | | | | | | | | | | | Liabilities: | | | | | | | | | | | | | | | | | | | | | Deposits | | $ | 4,205,631 | | | $ | 4,213,714 | | | $ | 2,833,516 | | | $ | 1,380,198 | | | $ | - | | Borrowings | | | 1,266,563 | | | | 1,255,283 | | | | - | | | | 1,221,324 | | | | 33,959 | | Interest rate swaps | | | 3,386 | | | | 3,386 | | | | - | | | | 3,386 | | | | - | | | | | | | | | | | | | | | | | | | | | | | Total liabilities | | $ | 5,475,580 | | | $ | 5,472,383 | | | $ | 2,833,516 | | | $ | 2,604,908 | | | $ | 33,959 | |
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