Investments in Securities - Weighted Average Lives of Trading Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value
Less than one year	$ 199,629	$ 99,973
Greater than one year and less than three years	93	5,323
Greater than three years and less than five years	413,165	472,774
Greater than five years	5,767,124	2,639,439
Securities, trading	6,380,011	3,217,509
Amortized Cost
Less than one year	199,700	99,978
Greater than one year and less than three years	98	5,365
Greater than three years and less than five years	435,063	475,600
Greater than five years	6,085,830	2,690,243
Amortized Cost	$ 6,720,691	$ 3,271,186