Fair Value Measurement and Fair Value of Financial Instruments (Quantitative Information for Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Quantitative information
Derivative assets - Fair value	$ 708,610	$ 330,316
Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	708,610	330,316
Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	171,004	49,679
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	310	421
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	171,004	49,679
Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	82,461	27,841
Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	15,493	1,014
Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	50,581
Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-invesment, Fair Value Disclosure	22,469	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		1,167
Other nonperforming assets | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure		1,167
Other nonperforming assets | Significant Unobservable Inputs (Level 3) | Fair value of collateral, contract value | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure		1,167
Investments in tax credit and other investments, net | Fair Value, Measurements, Nonrecurring
Quantitative information
Assets, fair value disclosure	6,216	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	6,216	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	6,216	3,076
Equity contracts | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	12,765	1,414
Equity contracts | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Quantitative information
Derivative assets - Fair value	$ 310	$ 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	59.00%	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	54.00%	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	65.00%	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 | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Loans held-for-investment, measurement input	13.00%	14.00%
Discount | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Loans held-for-investment, measurement input	4.00%	4.00%
Discount | Significant Unobservable Inputs (Level 3) | Discounted cash flows | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Loans held-for-investment, measurement input	15.00%	15.00%
Discount | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Loans held-for-investment, measurement input	10.00%	19.00%
Discount | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Minimum
Quantitative information
Loans held-for-investment, measurement input	10.00%	8.00%
Discount | Significant Unobservable Inputs (Level 3) | Fair value of collateral, discount | Fair Value, Measurements, Nonrecurring | Maximum
Quantitative information
Loans held-for-investment, measurement input	20.00%	20.00%
Selling cost | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring
Quantitative information
Loans held-for-investment, measurement input	8.00%
OREO, measurement input		0.08
Selling cost | Significant Unobservable Inputs (Level 3) | Fair value of property, selling cost | Fair Value, Measurements, Nonrecurring | Weighted Average
Quantitative information
Loans held-for-investment, measurement input	8.00%
OREO, measurement input		0.08
Derivatives not designated as hedging instruments
Quantitative information
Derivative assets - Fair value	$ 708,546	$ 330,316
Derivatives not designated as hedging instruments | Equity contracts
Quantitative information
Derivative assets - Fair value	$ 12,765	$ 1,414