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, 2019	Dec. 31, 2018	Dec. 31, 2017
Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	$ (35,358)	$ (9,056)	$ (22,624)
Non-PCI impaired loans | Commercial Lending
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(35,356)	(9,071)	(20,122)
Non-PCI impaired loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(35,365)	(9,341)	(19,703)
Non-PCI impaired loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	9	270	(272)
Non-PCI impaired loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	0	0	(147)
Non-PCI impaired loans | Commercial Lending | Total CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	9	270	(419)
Non-PCI impaired loans | Consumer Lending
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(2)	15	(2,502)
Non-PCI impaired loans | Consumer Lending | Residential loan
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(2)	15	(11)
Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	0	15	(11)
Non-PCI impaired loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(2)	0	0
Non-PCI impaired loans | Consumer Lending | Other consumer
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	0	0	(2,491)
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	(8)	0	(1)
Investments in tax credit and other investments, net
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in fair value of assets	$ (13,023)	$ 0	$ 0