Fair Value Measurement and Fair Value of Financial Instruments (Increase (Decrease) in Fair Value of Assets Measured on a Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ (24,940)	$ (20,482)	$ (36,834)	$ (43,103)
Investments in tax credit and other investments, net
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	(1,703)	(583)	(11,573)
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	(1,020)	0	(1,023)
Other nonperforming assets
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	0	0	(3,000)
Commercial lending | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(24,943)	(20,482)	(39,147)	(43,103)
Commercial lending | Commercial and industrial (“C&I”) | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(24,928)	(20,484)	(38,855)	(43,109)
Commercial lending | Commercial real estate (“CRE”) | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(15)	2	(292)	6
Consumer lending | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	3	0	2,313	0
Consumer lending | HELOCs | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	3	0	(178)	0
Consumer lending | Other consumer | Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ 0	$ 0	$ 2,491	$ 0