Investment Securities (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Other than Temporary Impairment Losses, Investments	$ 0	$ 0	$ 0
Asset-backed securities mortgage portfolio, maturity term	15 years
Debt Securities, Available-for-sale, Amortized Cost	$ 1,187,499,000	1,028,883,000
Debt Securities, Held-to-maturity, Transfer, Amount	373,900,000	0	0
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	19,095,000	0	0
Pledged Financial Instruments, Not Separately Reported, Securities	370,000,000	332,000,000
Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements	197,000,000	280,000,000
Pledged Financial Instruments, Not Separately Reported, Securities for Federal Home Loan Bank	18,000,000	22,000,000
Schedule of Repurchase Agreement Counterparties with Whom Repurchase Agreements Exceed 10 Percent of Stockholders' Equity [Table Text Block]	$ 0
Percentage of amount greater than shareholder's equity	10.00%
Debt Securities, Available-for-sale, Realized Loss	$ 692,000	2,600,000
Debt Securities, Available-for-sale, Realized Gain	271,000	60,000
Debt Securities, Held-to-maturity	0	351,808,000
Debt Securities, Held-to-maturity, Sold, Realized Gain (Loss)		$ 300,000
percent of held to securities sold paid down		96.30%
Debt Securities sold at a loss [Domain]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 245,000,000.0
Available-for-sale Securities, Amortized Cost Basis	62,400,000
Securities sold at a gain [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		2,000,000.0
Available-for-sale Securities, Amortized Cost Basis	29,100,000
Debt Securities, Held-to-maturity		$ 7,400,000
Available-for-sale Securities, Equity Securities			444,000
Debt and Equity Securities, Realized Gain (Loss)			$ 1,800,000
Residential mortgage-backed securities
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	581,000,000.0
Collateralized mortgage-backed securities
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 303,600,000

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Investments in Debt and Marketable Securities, Asset-backed Securities, Mortgage Portfolio Description, Mortgage Term

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Percentage of amount greater than shareholder's equity.

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percent of held to securities sold paid down

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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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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.

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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Amount of realized gain (loss) on investment in debt and equity securities.

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Amount of realized gain 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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Amount of realized loss 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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Amount of investment in debt security, measured at amortized cost, transferred to investment in debt security, measured at fair value, with change in fair value recognized in other comprehensive income (available-for-sale) and net income (trading).

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

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Amount of gain (loss) on sale of investment in debt security measured at amortized cost (held-to-maturity), including other-than-temporary impairment (OTTI).

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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.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification.

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The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for FHLB debt obligations, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

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The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for repurchase agreements, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

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Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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The amount at risk under repurchase agreements is defined as the excess of carrying amount (or market value, if higher than the carrying amount or if there is no carrying amount) of the securities or other assets sold under agreement to repurchase, including accrued interest plus any cash or other assets on deposit to secure the repurchase obligation, over the amount of the repurchase liability (adjusted for accrued interest).

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