Variable Interest Entities - Amortization Expense and Tax Credits and Other Tax Benefits (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in Qualified Affordable Housing Projects
Amortization expense	$ 7,656	$ 6,289	$ 4,926
Tax credits and other tax benefits recognized	$ 10,382	$ 8,547	$ 6,550