Derivative Instruments and Hedging Activities - Balance Sheet Disclosures (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Interest rate swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	166,866,000	43,733,000
Derivatives designated as hedging instruments
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	4,869,000	1,713,000
Notional Amount	1,037,147,000	187,281,000
Derivatives designated as hedging instruments | Cash flow hedge interest rate swaps
Derivative [Line Items]
Notional Amount	900,000,000
Derivatives designated as hedging instruments | Cash flow hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	4,722,000	1,484,000
Notional Amount	1,030,000,000	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	147,000	229,000
Notional Amount	7,147,000	7,281,000
Derivatives not designated as hedging instruments
Derivative [Line Items]
Other Assets	468,275,000	158,532,000
Other Liabilities	165,404,000	42,213,000
Notional Amount	7,852,326,000	4,255,866,000
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Other Assets	467,606,000	158,382,000
Other Liabilities	161,997,000	42,020,000
Notional Amount	7,293,947,000	4,113,106,000
Derivatives not designated as hedging instruments | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	669,000	150,000
Other Liabilities	3,407,000	193,000
Notional Amount	$ 558,379,000	$ 142,760,000