Restructuring Charges - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended	15 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring charge	$ 417	$ 1,002	$ 1,156	$ 1,738
Accrued Liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring liability	1,100		1,100		$ 700
Employee Severance and Termination
Restructuring Cost and Reserve [Line Items]
Restructuring charge	700		1,200
Contract Termination | Accrued Liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring charge					700
2014 Plan
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated (employee) | employee						290
Restructuring costs incurred for the 2014 plan						$ 27,000
Restructuring liability	1,075		1,075		2,781
2014 Plan | Employee Severance and Termination
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred for the 2014 plan						20,000
Restructuring liability	85		85		1,791
2014 Plan | Professional Fees, Office Closures and Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred for the 2014 plan						$ 7,000
Restructuring liability	$ 990		$ 990		$ 990