Investments - Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities Available for Sale - Amortized Cost
Due in 1 year or less	$ 47,535
Due after 1 year through 5 years	3,008,773
Due after 5 years through 10 years	2,269,752
Due after 10 years	2,373,467
Amortized Cost	7,699,527
Mortgage and asset-backed securities	1,023,715
Totals before allowance for credit losses	8,723,242	$ 8,604,250
Allowance for Credit Losses	0	0
Totals	8,723,242
Debt Securities Available for Sale - Fair Value
Due in 1 year or less	47,549
Due after 1 year through 5 years	2,980,577
Due after 5 years through 10 years	2,127,532
Due after 10 years	2,045,082
Fair Value	7,200,740
Mortgage and asset-backed securities	960,212
Allowance for credit losses	0
Total	$ 8,160,952	$ 9,068,946