Fair Value Measurement and Fair Value of Financial Instruments (Carrying Amounts of Assets Included on the Consolidated Balance Sheet That Had Fair Value Changes Measured on a Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	$ 45,481	$ 38,188
OREO nonrecurring fair value changes
Fair Value, Assets Measured on a Nonrecurring Basis
OREO		9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | OREO nonrecurring fair value changes
Fair Value, Assets Measured on a Nonrecurring Basis
OREO		0
Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Significant Other Observable Inputs (Level 2) | OREO nonrecurring fair value changes
Fair Value, Assets Measured on a Nonrecurring Basis
OREO		0
Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	45,481	38,188
Significant Unobservable Inputs (Level 3) | OREO nonrecurring fair value changes
Fair Value, Assets Measured on a Nonrecurring Basis
OREO		9
Commercial lending | Commercial and industrial (“C&I”) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	37,453	31,404
Commercial lending | Commercial and industrial (“C&I”) | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Commercial lending | Commercial and industrial (“C&I”) | Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Commercial lending | Commercial and industrial (“C&I”) | Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	37,453	31,404
Commercial lending | Commercial real estate (“CRE”) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	4,726	2,667
Commercial lending | Commercial real estate (“CRE”) | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Commercial lending | Commercial real estate (“CRE”) | Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Commercial lending | Commercial real estate (“CRE”) | Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	4,726	2,667
Commercial lending | Construction and land | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans		3,973
Commercial lending | Construction and land | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans		0
Commercial lending | Construction and land | Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans		0
Commercial lending | Construction and land | Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans		3,973
Consumer lending | Real estate loan | Single-family residential | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	2,567	144
Consumer lending | Real estate loan | Single-family residential | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Consumer lending | Real estate loan | Single-family residential | Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0	0
Consumer lending | Real estate loan | Single-family residential | Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	2,567	$ 144
Consumer lending | HELOCs | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	735
Consumer lending | HELOCs | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0
Consumer lending | HELOCs | Significant Other Observable Inputs (Level 2) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	0
Consumer lending | HELOCs | Significant Unobservable Inputs (Level 3) | Non-PCI impaired loans
Fair Value, Assets Measured on a Nonrecurring Basis
Non-PCI impaired loans	$ 735