Annual report pursuant to Section 13 and 15(d)

Debt (Senior Notes) (Details)

v3.10.0.1
Debt (Senior Notes) (Details) - Senior notes
$ in Millions
Dec. 31, 2018
USD ($)
Debt Instrument [Line Items]  
Aggregate unamortized premium $ 28.3
2021 Senior Notes  
Debt Instrument [Line Items]  
Interest rate 6.75%
2025 Senior Notes  
Debt Instrument [Line Items]  
Interest rate 6.875%