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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