Fair Value Measurement and Fair Value of Financial Instruments (Quantitative Information for Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Quantitative information
Derivative assets - Fair value	$ 242,876	$ 107,816
Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	242,876	107,816
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	392	673
Significant Unobservable Inputs (Level 3) | Individual analysis of each investment, expected future tax benefits and distributions | Fair Value, Measurements, Nonrecurring
Quantitative information
Investments in tax credit and other investments, net	0
Non-PCI Loans | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	39,186	32,858
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	39,186	32,858
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Non-PCI impaired loans	9,595	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	26,798	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	2,793	11,499
OREO | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	130
OREO | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	130
OREO | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
OREO	130
Equity warrants | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	1,985	1,951
Equity warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	$ 392	$ 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	49.00%
Equity volatility | Equity warrants | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Minimum
Quantitative information
Measurement input	43.00%
Equity volatility | Equity warrants | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Maximum
Quantitative information
Measurement input	51.00%
Liquidity discount | Equity warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Measurement input	47.00%
Liquidity discount | Equity warrants | Significant Unobservable Inputs (Level 3) | 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	9.00%	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	14.00%	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	37.00%	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	55.00%	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	8.00%
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	8.00%