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Qualified Affordable Housing Project Investments - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Investment for qualified affordable housing projects	$ 8,600,000	$ 9,500,000
Unfunded commitments related to the investments in qualified affordable housing projects	4,200,000	6,800,000
Amortization expense	900,000	644,000	$ 316,000
Recognized tax credits from its investment in affordable housing tax credits	1,100,000	573,000	275,000
Impairment losses	$ 0	$ 0	$ 0
Minimum
Schedule Of Equity Method Investments [Line Items]
Expected year in which commitments are fulfilled	2020
Maximum
Schedule Of Equity Method Investments [Line Items]
Expected year in which commitments are fulfilled	2027

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- Definition

Investment in affordable housing tax credits.

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Year in which contingent commitments to qualified affordable housing project investments are expected to be paid, in CCYY format.

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- Definition

Amount of investment in qualified affordable housing projects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount of amortization expense of investment in qualified affordable housing projects.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=118954083&loc=SL6284422-111562

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Amount of commitment or contingent commitments to qualified affordable housing project investments.

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-Topic 323
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