Debt Securities Held-to-Maturity - Summary of Mortgage-Backed Securities Held-to-Maturity (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 8,762,000	$ 9,505,000
Gross Unrealized Gains	129,000	0
Gross Unrealized Losses	5,000	256,000
Estimated Fair Value	8,886,000	9,249,000
Sales of held-to-maturity securities	0	0	$ 0
Held-to-maturity securities pledged to secured repurchase agreements and deposits	7,400,000	6,500,000
Mortgage-Backed Securities, Pass-Through Certificates
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	8,762,000	9,505,000
Gross Unrealized Gains	129,000	0
Gross Unrealized Losses	5,000	256,000
Estimated Fair Value	$ 8,886,000	$ 9,249,000

Amount of investment in debt security, measured at amortized cost, sold.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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-Subparagraph (a)
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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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-Publisher FASB
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of restricted investment in debt security measured at amortized cost (held-to-maturity).

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