Fair Value Measurement and Fair Value of Financial Instruments (Quantitative Information for Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Quantitative information
Derivative assets - Fair value	$ 358,639	$ 107,816
Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	358,639	107,816
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	402	673
Non-PCI Loans | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	43,851	32,858
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	43,851	32,858
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	4,407	16,921
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	14,094	2,751
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans		1,687
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	25,350	11,499
OREO | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	590
OREO | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	590
OREO | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	590
Investments in tax credit and other investments, net | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	830
Investments in tax credit and other investments, net | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	830
Investments in tax credit and other investments, net | Significant Unobservable Inputs (Level 3) | Individual analysis of each investment, expected future tax benefits and distributions | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	830
Equity warrants | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	1,542	1,951
Equity warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	$ 402	$ 673
Equity volatility | Equity warrants | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	54.00%	51.00%
Equity volatility | Equity warrants | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Minimum
Quantitative information
Measurement input	45.00%	49.00%
Equity volatility | Equity warrants | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Maximum
Quantitative information
Measurement input	56.00%	52.00%
Liquidity discount | Equity warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Measurement input	47.00%	47.00%
Liquidity discount | Equity warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	47.00%	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	7.00%	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	12.00%	7.00%
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	34.00%	21.00%
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%	15.00%
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	50.00%	50.00%
Selling cost | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans, measurement input		8.00%
Selling cost | Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Non-PCI impaired loans, measurement input		8.00%
Selling cost | OREO | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO, measurement input	0.08
Selling cost | OREO | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
OREO, measurement input	0.08
Derivatives not designated as hedging instruments
Quantitative information
Derivative assets - Fair value	$ 358,639	$ 107,816
Derivatives not designated as hedging instruments | Equity warrants
Quantitative information
Derivative assets - Fair value	$ 1,542	$ 1,951