Fair Value Accounting (Fair Value Inputs, Quantitative Information) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Measurements, Recurring | Trust Preferred Securities | Discounted cash flow analysis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spread embedded in discount rate	3.98%		4.42%
Fair Value, Measurements, Recurring | Visa Derivative | Discounted cash flow analysis | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated timing of resolution of covered litigation		1 year	1 year
Fair Value, Measurements, Recurring | Visa Derivative | Discounted cash flow analysis | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated timing of resolution of covered litigation		4 years	5 years
Fair Value, Measurements, Recurring | Private Equity Investments
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount of lack of liquidity		15.00%
Fair Value, Measurements, Recurring | Private Equity Investments | Individual analysis of each investee company
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount of lack of liquidity			15.00%
Fair Value, Measurements, Recurring | Level 3 | Earnout Liabilities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	$ 11,348	$ 11,348	$ 14,000
Fair Value, Measurements, Recurring | Level 3 | Visa Derivative
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	4,330	4,330
Fair Value, Measurements, Recurring | Level 3 | Visa Derivative | Discounted cash flow analysis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring			5,768
Fair Value, Measurements, Recurring | Level 3 | Trust Preferred Securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value disclosure	1,935	1,935	1,796
Fair Value, Measurements, Recurring | Level 3 | Private Equity Investments | Individual analysis of each investee company
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value disclosure	15,771	15,771	$ 25,493
Fair Value, Measurements, Recurring | Level 3 | GGL/SBA Loans Servicing Asset
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value disclosure	$ 4,101	$ 4,101
Fair Value, Measurements, Nonrecurring | Collateral Dependent Impaired Loans | Third-party appraised value of collateral less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		0.00%	0.00%
Estimated selling costs		0.00%	0.00%
Fair Value, Measurements, Nonrecurring | Collateral Dependent Impaired Loans | Third-party appraised value of collateral less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		50.00%	52.00%
Estimated selling costs		10.00%	10.00%
Fair Value, Measurements, Nonrecurring | Collateral Dependent Impaired Loans | Third-party appraised value of collateral less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		15.00%	25.00%
Estimated selling costs		7.00%	7.00%
Fair Value, Measurements, Nonrecurring | Other Loans Held for Sale | Third-party appraised value of real estate less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		5.00%	0.00%
Estimated selling costs		0.00%	0.00%
Fair Value, Measurements, Nonrecurring | Other Loans Held for Sale | Third-party appraised value of real estate less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		99.00%	3.00%
Estimated selling costs		10.00%	10.00%
Fair Value, Measurements, Nonrecurring | Other Loans Held for Sale | Third-party appraised value of real estate less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		54.00%	3.00%
Estimated selling costs		2.00%	7.00%
Fair Value, Measurements, Nonrecurring | Other Real Estate | Third-party appraised value of real estate less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		0.00%	0.00%
Estimated selling costs		0.00%	0.00%
Fair Value, Measurements, Nonrecurring | Other Real Estate | Third-party appraised value of real estate less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		85.00%	10.00%
Estimated selling costs		10.00%	10.00%
Fair Value, Measurements, Nonrecurring | Other Real Estate | Third-party appraised value of real estate less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		35.00%	5.00%
Estimated selling costs		7.00%	7.00%
Fair Value, Measurements, Nonrecurring | Other Assets Held for Sale | Third-party appraised value less estimated selling costs or BOV | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		21.00%	0.00%
Estimated selling costs		0.00%	0.00%
Fair Value, Measurements, Nonrecurring | Other Assets Held for Sale | Third-party appraised value less estimated selling costs or BOV | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		52.00%	81.00%
Estimated selling costs		10.00%	10.00%
Fair Value, Measurements, Nonrecurring | Other Assets Held for Sale | Third-party appraised value less estimated selling costs or BOV | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		25.00%	47.00%
Estimated selling costs		7.00%	7.00%