Derivative Instruments and Hedging Activities - Balance Sheet Disclosures (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Interest rate swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	160,394,000	43,733,000
Derivatives designated as hedging instruments
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	2,711,000	1,713,000
Notional Amount	737,215,000	187,281,000
Derivatives designated as hedging instruments | Cash flow hedge interest rate swaps
Derivative [Line Items]
Notional Amount	600,000,000
Derivatives designated as hedging instruments | Cash flow hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	2,493,000	1,484,000
Notional Amount	730,000,000	180,000,000
Derivatives designated as hedging instruments | Fair value hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	218,000	229,000
Notional Amount	7,215,000	7,281,000
Derivatives not designated as hedging instruments
Derivative [Line Items]
Other Assets	438,183,000	158,532,000
Other Liabilities	160,659,000	42,213,000
Notional Amount	5,606,820,000	4,255,866,000
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Other Assets	436,497,000	158,382,000
Other Liabilities	157,683,000	42,020,000
Notional Amount	5,226,704,000	4,113,106,000
Derivatives not designated as hedging instruments | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	1,686,000	150,000
Other Liabilities	2,976,000	193,000
Notional Amount	$ 380,116,000	$ 142,760,000