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Income Taxes - Significant Components of Temporary Differences (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Jan. 01, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Deferred Tax Assets: |  |  |
Allowance for credit losses | $ 26,051 |  | $ 13,798
Lease liabilities | 11,368 |  | 11,257
State net operating loss carryforwards | 5,489 |  | 5,134
Net adjustment to funded status of pension | 4,692 |  | 5,438
Low income housing partnerships | 3,996 |  | 3,494
Other employee benefits | 2,050 |  | 3,039
Other | 3,798 |  | 1,856
Gross Deferred Tax Assets | 57,444 |  | 44,016
Less: Valuation allowance | (5,489) |  | (5,134)
Total Deferred Tax Assets | 51,955 |  | 38,882
Deferred Tax Liabilities: |  |  |
Right-of-use lease assets | (10,141) |  | (10,476)
Net unrealized gains on securities available-for-sale | (7,125) |  | (2,570)
Deferred loan income | (6,796) |  | (3,555)
Prepaid pension | (5,209) |  | (5,971)
Purchase accounting adjustments | (1,971) |  | (1,269)
Depreciation on premises and equipment | (1,275) |  | (592)
Other | (1,245) |  | (1,243)
Total Deferred Tax liabilities | (33,762) |  | (25,676)
Net Deferred Tax Asset | $ 18,193 | $ 13,206 | $ 13,206

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