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	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ (23,999)	$ 4,537	$ (25,819)	$ 514
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(3)	0	(3)	0
Investments in tax credit and other investments, net
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	(2,892)	0	(9,870)	0
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)	4,544	(25,823)	595
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	66	4	(23)
Consumer lending | Real estate loan | Single-family residential | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	0	0	0	15
Consumer lending | HELOCs | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Increase (decrease) in value of assets	$ 0	$ (73)	$ 0	$ (73)