Annual report pursuant to Section 13 and 15(d)

Severance Expense - Narrative (Details)

v3.10.0.1
Severance Expense - Narrative (Details)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2018
USD ($)
employee
Mar. 31, 2018
USD ($)
employee
Mar. 31, 2017
USD ($)
employee
Dec. 31, 2016
USD ($)
position
Restructuring Cost and Reserve [Line Items]        
Number of positions eliminated 45 70 40 6
Selling, general and administrative expenses        
Restructuring Cost and Reserve [Line Items]        
Severance expenses $ 2.4 $ 3.1 $ 4.6 $ 1.7