Investments in Qualified Affordable Housing Partnerships, Tax Credit and Other Investments, Net and Variable Interest Entities (Investments in Tax Credit and Other Investments, Net) (Details)	3 Months Ended
	Mar. 31, 2021 USD ($) credit	Mar. 31, 2020 USD ($) credit	Dec. 31, 2020 USD ($)
Investments in Tax Credit and Other Investments, Net, And Related Unfunded Commitments [Abstract]
Investments in tax credit and other investments, net	$ 361,438,000		$ 266,525,000
Accrued expenses and other liabilities — Unfunded commitments	192,644,000		105,282,000
Amortization expense of tax credit and other investments	25,358,000	$ 18,782,000
Unrealized gains (losses) recognized on equity securities with readily determinable fair values	(497,000)	38,000
Adjustments to equity securities without readily determinable fair values	$ 0	$ 0
Number of recovered historic tax credit investments | credit	1	1
Investment in tax credit and other investments
Investments in Tax Credit and Other Investments, Net, And Related Unfunded Commitments [Abstract]
OTTI charges	$ 0	$ 0
Pre-tax recoveries	374,000	$ 150,000
Tax credit investments
Investments in Tax Credit and Other Investments, Net, And Related Unfunded Commitments [Abstract]
Equity securities with readily determinable fair values	26,700,000		31,300,000
Investments in Tax Credit and Other Investments and Other Assets
Investments in Tax Credit and Other Investments, Net, And Related Unfunded Commitments [Abstract]
Equity securities without readily determinable fair values	$ 27,200,000		$ 23,700,000