Fair Value Measurement and Fair Value of Financial Instruments (Quantitative Information for Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Quantitative information
Derivative assets - Fair value	$ 834,204	$ 330,316
Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	834,204	330,316
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	713	421
Loans | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	33,901
Loans | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	33,901
Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	25,140
Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	5,712
Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	558
Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans	2,491
Non-PCI Loans | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans		49,679
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans		49,679
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans		27,841
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans		1,014
Non-PCI Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans		20,824
OREO | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure		125
OREO | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure		125
OREO | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure		125
Other nonperforming assets | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	867
Other nonperforming assets | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	867
Other nonperforming assets | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	867
Investments in tax credit and other investments, net | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	3,076	3,076
Investments in tax credit and other investments, net | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	3,076	3,076
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
Assets, fair value disclosure	3,076	3,076
Equity contracts | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	1,128	1,414
Equity contracts | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	$ 713	$ 421
Equity volatility | Equity contracts | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	82.00%	42.00%
Equity volatility | Equity contracts | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Minimum
Quantitative information
Measurement input	72.00%	39.00%
Equity volatility | Equity contracts | Significant Unobservable Inputs (Level 3) | Black-Scholes option pricing model | Fair Value, Measurements, Recurring | Maximum
Quantitative information
Measurement input	86.00%	44.00%
Liquidity discount | Equity contracts | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Measurement input	47.00%	47.00%
Liquidity discount | Equity contracts | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Weighted Average
Quantitative information
Measurement input	47.00%	47.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Impaired loans, measurement input	12.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Impaired loans, measurement input	4.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Impaired loans, measurement input	15.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Impaired loans, measurement input	9.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Impaired loans, measurement input	8.00%
Discount | Loans | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Impaired loans, measurement input	9.00%
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		14.00%
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%
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		15.00%
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		19.00%
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		8.00%
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		20.00%
Selling cost | Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Impaired loans, measurement input	8.00%
Selling cost | Loans | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
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	$ 834,131	$ 330,316
Derivatives not designated as hedging instruments | Equity contracts
Quantitative information
Derivative assets - Fair value	$ 1,128	$ 1,414