Fair Value Measurement and Fair Value of Financial Instruments (Increase (Decrease) in Value of Assets Measured on a Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans held-for-investment
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	$ (57,127)	$ (35,358)	$ (9,056)
Loans held-for-investment | Commercial Lending
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(59,443)	(35,356)	(9,071)
Loans held-for-investment | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(48,154)	(35,365)	(9,341)
Loans held-for-investment | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(11,289)	9	270
Loans held-for-investment | Consumer Lending
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	2,316	(2)	15
Loans held-for-investment | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	0	0	15
Loans held-for-investment | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(175)	(2)	0
Loans held-for-investment | Consumer Lending | Other consumer
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	2,491	0	0
Investments in tax credit and other investments, net
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(3,868)	(13,023)	0
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(3,680)	(8)	0
Other nonperforming assets
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	$ 0	$ (3,000)	$ 0