Fair Value of Assets & Liabilities - Nonrecurring Fair Value Measurements (Details) - USD ($) $ in Thousands		Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		$ 13,263		$ 14,033
Loans, net of unearned income		32,708,937	[1]	31,061,111	[1]	$ 29,712,810
OREO	[2]	15,134		17,838
Non Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income		66,062		42,208
OREO		13,177		15,660
Other assets		9,835		10,608
Non Recurring | Small Business Administration And USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		644,219		493,524
Non Recurring | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		504		516
Non Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income		0		0
OREO		0		0
Other assets		0		0
Non Recurring | Level 1 | Small Business Administration And USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		0		0
Non Recurring | Level 1 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		0		0
Non Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income		0		0
OREO		0		0
Other assets		0		0
Non Recurring | Level 2 | Small Business Administration And USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		643,445		492,595
Non Recurring | Level 2 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		0		0
Non Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income		66,062		42,208
OREO		13,177		15,660
Other assets		9,835		10,608
Non Recurring | Level 3 | Small Business Administration And USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		774		929
Non Recurring | Level 3 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale		$ 504		$ 516

[1] June 30, 2020 and December 31, 2019 include $16.9 million and $18.8 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.

[2] June 30, 2020 and December 31, 2019 include $7.8 million and $9.2 million, respectively, of foreclosed residential real estate.