Fair Value Measurement and Fair Value of Financial Instruments (Fair Value Adjustments of Assets Measured on a Nonrecurring Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans held-for-sale
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	$ 61	$ 5,600	$ 3,000
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(22,624)	(26,212)	(9,029)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(19,703)	(27,106)	(5,612)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(272)	1,084	(2,629)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Commercial Lending | Residential loan | Multifamily
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	0	0	(115)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(147)	0	(118)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(11)	(224)	(496)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	0	34	(59)
Fair Value, Measurements, Nonrecurring | Non-PCI Impaired Loans | Consumer Lending | Other consumer
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(2,491)	0	0
Fair Value, Measurements, Nonrecurring | OREO
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	(1)	(23)	(233)
Fair Value, Measurements, Nonrecurring | Loans held-for-sale
Fair Value, Assets Measured on a Nonrecurring Basis
Fair value adjustment of assets	$ 0	$ (5,565)	$ (1,991)