Quarterly report pursuant to Section 13 or 15(d)

Variable Interest Entities - (Summary of Key Terms of NMTC Transactions) (Details)

v3.19.2
Variable Interest Entities - (Summary of Key Terms of NMTC Transactions) (Details) - Primary Beneficiary
$ in Millions
6 Months Ended
Jun. 30, 2019
USD ($)
NMTC 2  
Variable Interest Entity [Line Items]  
Loans to VIE $ 37.7
Interest rate percentage 1.00%
NMTC 2 | US Bancorp  
Variable Interest Entity [Line Items]  
Amount to other entity $ 17.5
NMTC 2 | Unicom  
Variable Interest Entity [Line Items]  
Amount to other entity $ 52.0
NMTC 2 | Unicom | Minimum  
Variable Interest Entity [Line Items]  
Interest rate percentage 0.71%
NMTC 2 | Unicom | Maximum  
Variable Interest Entity [Line Items]  
Interest rate percentage 0.77%
NMTC 3  
Variable Interest Entity [Line Items]  
Loans to VIE $ 8.2
Interest rate percentage 1.00%
NMTC 3 | US Bancorp  
Variable Interest Entity [Line Items]  
Amount to other entity $ 3.8
NMTC 3 | Unicom  
Variable Interest Entity [Line Items]  
Interest rate percentage 1.35%
Amount to other entity $ 12.0
NMTC 4  
Variable Interest Entity [Line Items]  
Loans to VIE $ 6.7
Interest rate percentage 1.00%
NMTC 4 | US Bancorp  
Variable Interest Entity [Line Items]  
Amount to other entity $ 3.3
NMTC 4 | Unicom  
Variable Interest Entity [Line Items]  
Interest rate percentage 0.73%
Amount to other entity $ 9.8
NMTC 5  
Variable Interest Entity [Line Items]  
Loans to VIE $ 10.4
Interest rate percentage 1.00%
NMTC 5 | US Bancorp  
Variable Interest Entity [Line Items]  
Amount to other entity $ 5.1
NMTC 5 | Unicom  
Variable Interest Entity [Line Items]  
Amount to other entity $ 14.7
NMTC 5 | Unicom | Minimum  
Variable Interest Entity [Line Items]  
Interest rate percentage 0.67%
NMTC 5 | Unicom | Maximum  
Variable Interest Entity [Line Items]  
Interest rate percentage 1.24%