Restructuring Expenses (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2019 employee	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Employees displaced through workforce reduction | employee	110
Restructuring charges		$ 7,420	$ 0
Restructuring Reserve [Roll Forward]
Accrued restructuring, beginning of period		0
Workforce reduction payments		(2,159)
Contract termination cost payments		(59)
Other payments		(144)
Accrued restructuring, end of period		5,058
Workforce reduction
Restructuring Cost and Reserve [Line Items]
Restructuring charges		7,034
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		229
Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 157