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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ (9,181)		$ (28,414)
Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		$ (23,999)		$ (25,819)
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	(3)	0	(3)
Investments in tax credit and other investments, net
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(733)	(2,892)	(583)	(9,870)
Other nonperforming assets
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	0	0	(3,000)
Commercial lending | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(9,117)		(30,648)
Commercial lending | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		(23,999)		(25,819)
Commercial lending | Commercial and industrial (“C&I”) | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(8,846)		(30,372)
Commercial lending | Commercial and industrial (“C&I”) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		(24,001)		(25,823)
Commercial lending | Commercial real estate (“CRE”) | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(271)		(276)
Commercial lending | Commercial real estate (“CRE”) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		2		4
Consumer lending | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(64)		2,234
Consumer lending | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		0		0
Consumer lending | HELOCs | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(64)		(257)
Consumer lending | HELOCs | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		0		0
Consumer lending | Other consumer | Individually evaluated loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ 0		$ 2,491
Consumer lending | Other consumer | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets		$ 0		$ 0