Variable Interest Entities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Subordinated Borrowing [Line Items]
Federal tax credits recognized in tax expense	$ 530	$ 510	$ 1,030	$ 1,010
Investment tax credits	9,480	$ 1,080	9,480	$ 3,000
Investment carrying amount	8,029,359		8,029,359		$ 8,096,289
Unfunded capital and other commitments	7,118,692		7,118,692		7,126,825
Maximum exposure to loss, unconsolidated VIEs	52,447		52,447		50,319
Variable interest entity, primary beneficiary
Subordinated Borrowing [Line Items]
Investment carrying amount	67,120		67,120		59,080
Unfunded capital and other commitments	6,750		6,750		0
Variable interest entity, not primary beneficiary
Subordinated Borrowing [Line Items]
Investment carrying amount	20,090		20,090		35,968
Unfunded capital and other commitments	$ 16,143		$ 16,143		$ 29,670