Restructuring - Additional Information (Details)		3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2015 employee	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) employee	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges		$ 5,439,000	$ 212,000	$ 5,439,000	$ 8,544,000
Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring Charges, Pre Tax		6,700,000
Restructuring charges, net of tax		5,700,000
Headcount reduction | employee				300
Restructuring and related charges		6,737,000
Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net of tax						$ 10,300,000
Number of terminations during period | employee	964
Number of terminations during period, percentage	15.50%
Restructuring and related charges			1,287,000	$ 0	14,791,000	$ 16,100,000
Restructuring charges excluding other | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges		5,400,000
Employee Severance and Lease Termination | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges		0	$ 200,000	0	$ 8,500,000
Minimum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges		12,000,000		12,000,000
Maximum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges		$ 15,000,000		$ 15,000,000