Derivatives and Balance Sheet Offsetting 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
Balance Sheet Offsetting [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ 0
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	3,100,000		$ 3,100,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	4,088,000	$ 0	19,779,000	$ 0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	76,000	0	76,000	0
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	24,489,000		24,489,000
Repurchase agreements, amounts offset in balance sheet	0		0		$ 0
Repurchase agreements, net amount presented in statement of financial position	24,489,000		24,489,000		61,094,000
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	(24,489,000)		(24,489,000)		(61,094,000)
Securities sold under agreements to repurchase, amount not offset	0		0		0
Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0		0		0
Derivative Asset	25,045,000		25,045,000		7,033,000
Derivative, Collateral, Obligation to Return Cash	0		0		0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	25,045,000		25,045,000		7,033,000
Derivative Liability, Gross Amounts Offset in Balance Sheets	0		0		0
Derivative Liability	25,046,000		25,046,000		7,033,000
Derivative, Collateral, Right to Reclaim Cash	25,046,000		25,046,000		3,235,000
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0		0		3,798,000
Interest rate collar [Domain]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0		0
Derivative Asset	19,703,000		19,703,000
Derivative, Collateral, Obligation to Return Cash	(19,703,000)		(19,703,000)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0		0
Available-for-sale Securities [Member]
Balance Sheet Offsetting [Line Items]
Securities Sold under Agreements to Repurchase, Gross	24,489,000		24,489,000		61,094,000
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax		$ 1,000	(2,000)	$ 9,000
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Assets [Member]
Balance Sheet Offsetting [Line Items]
Fair value of asset derivative instruments	25,045,000		25,045,000		7,033,000
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Liabilities [Member]
Balance Sheet Offsetting [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] | Other Assets [Member]
Balance Sheet Offsetting [Line Items]
Fair value of asset derivative instruments	19,703,000		19,703,000		0
Designated as Hedging Instrument [Member] | Interest rate collar [Domain] | Other Liabilities [Member]
Balance Sheet Offsetting [Line Items]
Fair value of liability derivative instruments	0		0		$ 0
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Balance Sheet Offsetting [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]
Balance Sheet Offsetting [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	$ 24,489,000		$ 24,489,000