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Derivatives and Balance Sheet Offsetting (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018 | Dec. 31, 2018
Derivative [Line Items] |  |  |  |  |
Gain (Loss) on Derivative Instruments, Net, Pretax | $ 0 |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 24,489,000 |  | $ 24,489,000 |  |
Secured Borrowings, Gross, Difference, Amount | 0 |  | 0 |  |
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 24,489,000 |  | 24,489,000 |  |
Maturity Overnight [Member] | U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 24,489,000 |  | 24,489,000 |  |
Maturity Less than 30 Days [Member] | U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 0 |  | 0 |  |
Maturity 30 to 90 Days [Member] | U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 0 |  | 0 |  |
Maturity Greater than 90 Days [Member] | U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement | 0 |  | 0 |  |
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Notional Amount | 396,500,000 |  | 396,500,000 |  | $ 366,700,000
Gain (Loss) on Derivative Instruments, Net, Pretax |  | $ 1,000 | (2,000) | $ 9,000 |
Not Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest Rate Contracts [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Fair value of asset derivative instruments | 25,045,000 |  | 25,045,000 |  | 7,033,000
Not Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest Rate Contracts [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Fair value of liability derivative instruments | 25,046,000 |  | 25,046,000 |  | 7,033,000
Designated as Hedging Instrument [Member] | Interest rate collar [Domain] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Notional Amount | 500,000,000.0 |  | 500,000,000.0 |  |
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate collar [Domain] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Fair value of asset derivative instruments | 19,703,000 |  | 19,703,000 |  | 0
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate collar [Domain] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Fair value of liability derivative instruments | $ 0 |  | $ 0 |  | $ 0

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