Derivative Financial Instruments Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral		$ 4,779	$ 7,522
Derivative Asset		133,158	292,291
Derivative Liability, Fair Value, Amount Offset Against Collateral		4,779	7,522
Derivative Liability		7,163	$ 347
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	$ 785	299
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	785	432
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	1,247	329
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	1,247	389
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	12,007	6,710
Derivative Asset, Fair Value, Gross Asset	40,565	13,012
Derivative Asset, Fair Value, Amount Offset Against Collateral	40,565	12,879
Derivative Asset	0	133
Derivative Liability, Fair Value, Amount Offset Against Collateral	12,007	6,650
Derivative Liability	$ 0	$ 60