Affordable Housing Tax Credits and Other Tax Benefits, Percentage

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Number Of Government Sponsored Securities

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Number Of Mortgage-Backed Securities

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Par Value Of Mortgage-Backed Securities Pledged To FRB

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Vertical Risk Retention, Percentage

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Amount of affordable housing tax credits and other tax benefits recognized.

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Amount of investment in qualified affordable housing projects.

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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).

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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cash inflow from sale of 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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Amount of commitment or contingent commitments to qualified affordable housing project investments.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Investments - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) security numberOfInvestments	Dec. 31, 2019 USD ($) security
Investment Holdings [Line Items]
Vertical risk retention interest	5.00%
Trading investments			$ 14,651	$ 0
Available-for-sale investments, cost			2,081,236	485,756
Par value of mortgage-backed securities pledged to FRB			748,000	252,000
Gain on equity securities investment		$ 8,000
Non-marketable securities investment			26,000	26,000
Low income housing tax credit investments			55,000	58,000
Low income housing tax credit investments, liability for unfunded commitments			22,000	29,000
Low income housing tax credit investments, tax credits and benefits			$ 1,000	$ 6,000
Low income housing tax credit investments, expected tax benefits recognized			25.00%
Minimum
Investment Holdings [Line Items]
Number of securities in net loss position \| numberOfInvestments			8
Maximum
Investment Holdings [Line Items]
Number of securities in net loss position \| numberOfInvestments			10
Mortgage-backed securities
Investment Holdings [Line Items]
Number of securities in net loss position \| security			3	33
Number of mortgage-backed securities \| security				107
Utah Housing Corporation bonds
Investment Holdings [Line Items]
Number of securities in net loss position \| security			0
Number of mortgage-backed securities \| security			3
U.S. government-sponsored enterprises and Treasuries
Investment Holdings [Line Items]
Number of securities in net loss position \| security			2
Number of government sponsored securities \| security			32
Ginnie Mae \| Mortgage-backed securities
Investment Holdings [Line Items]
Available-for-sale investments, cost			$ 38,000
Number of securities in net loss position \| security				18
Number of mortgage-backed securities \| security				33
Fannie Mae \| Mortgage-backed securities
Investment Holdings [Line Items]
Available-for-sale investments, cost			93,000
Freddie Mac \| Mortgage-backed securities
Investment Holdings [Line Items]
Available-for-sale investments, cost			$ 178,000
Student Loan
Investment Holdings [Line Items]
Private education loans sold	$ 1,700,000