Derivatives and Hedging Activities (Textual) (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Interest Receivable		$ (36,700,000)		$ (36,700,000)
Derivative, Net Liability Position, Aggregate Fair Value		93,000,000.0		$ 93,000,000.0		$ 26,000,000.0
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge				4 years 1 month 6 days
Gain (Loss) on Sales of Loans, Net		10,000,000.0	$ 5,500,000	$ 20,700,000	$ 9,500,000
Exposure to Institutional Counterparties		54,000,000.0		54,000,000.0		25,400,000
Amortization Of Deferred Hedge Gains Losses		0		0
Customer related positions		145,500,000		145,500,000		51,000,000.0
Fair Value Hedges, Net		0		0		0
Change in Fair Value on Loans Held for Sale		413,000	272,000	1,252,000	1,192,000
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Loss on Termination of Derivatives, before Tax		684,000	$ 0	684,000	$ 0
Interest rate swaps
Derivative [Line Items]
Interest Receivable	[1],[2]	(1,200,000)		(1,200,000)		(350,000)
Derivative, Notional Amount		925,000,000		925,000,000		925,000,000
Interest Payable, Current	[1],[2]	$ (75,000)		$ (75,000)		$ (4,000)
Interest rate collars on loans [Member]
Derivative [Line Items]
Derivative, Average Cap Interest Rate		2.73%		2.73%		2.73%
Derivative, Average Floor Interest Rate		2.20%		2.20%		2.02%
Derivative, Notional Amount		$ 400,000,000		$ 400,000,000		$ 400,000,000
Loan level swaps
Derivative [Line Items]
Interest Receivable	[1],[2]	(1,900,000)		(1,900,000)		(569,000)
Interest Payable, Current	[1],[2]	(1,900,000)		(1,900,000)		(569,000)
Interest rate swaps on borrowings [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 75,000,000		75,000,000		$ 75,000,000
Interest Income [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months				18,500,000
Interest Expense [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months				$ (999,000)

[1] All asset derivatives are located in other assets on the balance sheet.

[2] Approximately $1.2 million and $1.9 million of accrued interest receivable is included in the fair value of the interest rate and loan level asset derivatives, respectively, as of September 30, 2020. Accrued interest receivable of approximately and $350,000 and $569,000 was excluded from the fair value of the interest rate and loan level asset derivatives, respectively, as of December 31, 2019.