Fair Value Measurement and Fair Value of Financial Instruments (Carrying Amounts of Assets Included on the Consolidated Balance Sheets Measured on a Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on a Nonrecurring Basis
Loans held-for-sale		$ 22,703
Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	$ 38,188	70,154
Non-PCI impaired loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	31,404	52,172
Non-PCI impaired loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	2,667	14,908
Non-PCI impaired loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	3,973
Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	144	2,464
Non-PCI impaired loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	610
OREO
Fair Value, Assets Measured on a Nonrecurring Basis
OREO	9	345
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets Measured on a Nonrecurring Basis
Loans held-for-sale		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | OREO
Fair Value, Assets Measured on a Nonrecurring Basis
OREO	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets Measured on a Nonrecurring Basis
Loans held-for-sale		22,703
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	0
Significant Other Observable Inputs (Level 2) | OREO
Fair Value, Assets Measured on a Nonrecurring Basis
OREO	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets Measured on a Nonrecurring Basis
Loans held-for-sale		0
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	38,188	70,154
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans | Commercial Lending | C&I
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	31,404	52,172
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans | Commercial Lending | CRE
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	2,667	14,908
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans | Commercial Lending | Construction and land
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	3,973
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	144	2,464
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans | Consumer Lending | HELOCs
Fair Value, Assets Measured on a Nonrecurring Basis
Impaired loans	0	610
Significant Unobservable Inputs (Level 3) | OREO
Fair Value, Assets Measured on a Nonrecurring Basis
OREO	$ 9	$ 345