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Investments (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
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Debt Securities, Available-for-sale [Abstract] |  |
Amortized Cost | $ 1,078,474 | $ 913,978
Unrealized Gains | 38,261 | 9,551
Unrealized Losses | (922) | (5,411)
AFS securities | 1,115,813 | 918,118
Obligations of states and political subdivisions |  |
Debt Securities, Available-for-sale [Abstract] |  |
Amortized Cost | 119,608 | 115,632
Unrealized Gains | 7,627 | 2,779
Unrealized Losses | (115) | (328)
AFS securities | 127,120 | 118,083
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises |  |
Debt Securities, Available-for-sale [Abstract] |  |
Amortized Cost | 547,396 | 462,593
Unrealized Gains | 19,796 | 3,398
Unrealized Losses | (574) | (2,605)
AFS securities | 566,618 | 463,386
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises |  |
Debt Securities, Available-for-sale [Abstract] |  |
Amortized Cost | 399,937 | 325,200
Unrealized Gains | 10,652 | 3,183
Unrealized Losses | (135) | (2,478)
AFS securities | 410,454 | 325,905
Subordinated corporate bonds |  |
Debt Securities, Available-for-sale [Abstract] |  |
Amortized Cost | 11,533 | 10,553
Unrealized Gains | 186 | 191
Unrealized Losses | (98) | 0
AFS securities | $ 11,621 | $ 10,744

X
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References No definition available. + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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