Fair Value Measurement and Fair Value of Financial Instruments (Quantitative Information for Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Quantitative information
Derivative assets - Fair value	$ 99,103	$ 66,146
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	672	679
Non-PCI Loans | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	45,481	38,188
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	45,481	38,188
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	19,814	22,802
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	4,453	9,773
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	2,132	3,207
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	$ 19,082	2,406
OREO nonrecurring fair value losses | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO		9
OREO nonrecurring fair value losses | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO		9
OREO nonrecurring fair value losses | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO		$ 9
Volatility | Warrant | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	48.00%
Liquidity discount | Warrant | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	47.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Non-PCI impaired loans, measurement input	6.00%	6.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Non-PCI impaired loans, measurement input	4.00%	4.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Non-PCI impaired loans, measurement input	7.00%	10.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans, measurement input	100.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Non-PCI impaired loans, measurement input	100.00%	29.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Non-PCI impaired loans, measurement input		20.00%
Discount | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Non-PCI impaired loans, measurement input		32.00%
Selling cost | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans, measurement input	8.00%	8.00%
Selling cost | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Non-PCI impaired loans, measurement input	8.00%	8.00%
Selling cost | OREO nonrecurring fair value losses | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO, measurement input		8.00%
Selling cost | OREO nonrecurring fair value losses | Significant Unobservable Inputs (Level 3) | Fair value of property | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
OREO, measurement input		8.00%