Fair Value Measurements Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair value measurements at reporting date using:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	$ 6,752,894		$ 6,883,360
Fair value measurements at reporting date using: | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	0		0
Fair value measurements at reporting date using: | Significant  other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	0		0
Fair value measurements at reporting date using: | Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	6,752,894		$ 6,883,360
Fair value measurements at reporting date using: | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	97	$ 957
Fair value measurements at reporting date using: | Fair Value, Measurements, Nonrecurring | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	0	0
Fair value measurements at reporting date using: | Fair Value, Measurements, Nonrecurring | Significant  other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	0	0
Fair value measurements at reporting date using: | Fair Value, Measurements, Nonrecurring | Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets: Impaired loans	97	957
Gain (losses) from fair value changes | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (losses) from fair value changes	$ 21	$ 372