XML 109 R91.htm IDEA: XBRL DOCUMENT v3.10.0.1
Derivatives - Interest Rate Risk - Narratives (Details) - Derivatives designated as hedging instruments - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2018
Aug. 31, 2017
Interest rate swaps      
Derivatives      
Derivative average fixed interest rate   1.80%  
Interest income (expense) $ 0    
Deferred pre-tax losses to be reclassified during next 12 months   $ (3,200,000)  
Notional amount of interest rate swaps   500,000,000  
March 2022      
Derivatives      
Notional amount of interest rate swaps   $ 300,000,000 $ 300,000,000
Derivative liability     $ 700,000