Financial Derivatives - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Gain expected to be reclassified from AOCI to earnings over next 12 months	$ 4,600,000
Gain (loss) from interest rate swaps designated as cash flow hedges reclassified to earnings	0	$ 0
Investments held as collateral	0	0
Financial derivatives in net payable position	0	0
Notional amount	17,547,367,000	15,447,553,000
Exchange Cleared
Derivative [Line Items]
Notional amount	14,900,000,000	12,800,000,000
Interest Rate Swap
Derivative [Line Items]
Notional amount	17,500,000,000	15,400,000,000
Cash
Derivative [Line Items]
Cash held as collateral		1,300,000
Cash posted as collateral	16,600,000	11,200,000
Available-for-Sale Securities
Derivative [Line Items]
Cash posted as collateral	$ 177,900,000	$ 201,100,000