Derivatives and Hedging Activities (Textual) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Interest Receivable	$ 29,100,000	$ 36,700,000	$ 29,100,000	$ 36,700,000
Derivative, Net Liability Position, Aggregate Fair Value	35,900,000		$ 35,900,000		$ 79,800,000
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge			7 years 6 months
Gain (Loss) on Sales of Loans, Net	4,900,000	10,000,000	$ 17,200,000	20,700,000
Exposure to Institutional Counterparties	37,100,000		37,100,000		48,800,000
Customer related positions	71,800,000		71,800,000		127,200,000
Fair Value Hedges, Net	0		0		0
Change in Fair Value on Loans Held for Sale	(75,000)	413,000	(1,534,000)	1,252,000
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Loss on Termination of Derivatives, before Tax	0	$ 684,000	0	$ 684,000
Interest rate swaps
Derivative [Line Items]
Interest Receivable	1,200,000		1,200,000		1,200,000
Derivative, Notional Amount	1,025,000,000		1,025,000,000		925,000,000
Interest Payable, Current	$ (60,000)		$ (60,000)		$ (81,000)
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%		2.20%
Derivative, Notional Amount	$ 400,000,000		$ 400,000,000		$ 400,000,000
Loan level swaps
Derivative [Line Items]
Interest Receivable	1,600,000		1,600,000		2,000,000
Interest Payable, Current	(1,600,000)		(1,600,000)		(2,000,000)
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			19,000,000
Interest Expense [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			$ (509,000)