Securities - Amortized Cost and Estimated Fair Value of Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Securities available-for-sale:
Amortized Cost	$ 141,651	$ 230,012
Gross Unrealized Gains	4,304	5,762
Estimated Fair Value	145,955	235,774
Agency mortgage-backed securities
Securities available-for-sale:
Amortized Cost	126,682	170,215
Gross Unrealized Gains	4,210	5,111
Estimated Fair Value	130,892	175,326
U.S. Treasury
Securities available-for-sale:
Amortized Cost	14,969	59,797
Gross Unrealized Gains	94	651
Estimated Fair Value	$ 15,063	$ 60,448

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).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
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Amount of 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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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