Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Cash Flow Hedges
Interest expense	$ 90,037	$ 117,811	$ 290,987	$ 428,649
Trading
Total	12,913	5,820	30,043	58,965
Designated as Hedging Instrument
Fair Value Hedges
Interest recognized on derivatives	21,763	23,851	67,230	47,906
Hedged items recorded in interest expense	20,551	24,451	72,774	(116,500)
Derivatives recorded in interest expense	(20,602)	(24,458)	(72,787)	116,870
Trading
Total	21,712	23,844	67,217	48,276
Designated as Hedging Instrument | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Reclassification out of Accumulated Other Comprehensive Income
Cash Flow Hedges
Interest expense	(5,228)	(5,176)	(15,791)	(10,922)
Trading
Trading
Change in fair value of future interest payments recorded in earnings	(3,571)	(12,848)	(21,383)	21,611
Total	$ (3,571)	$ (12,848)	$ (21,383)	$ 21,611