Restructuring Costs - Summary of Pre-tax Costs Incurred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ (66)	$ 3,525	$ 1,785
Employee Severance
Restructuring Cost And Reserve [Line Items]
Restructuring costs	0	73	498
Contract Termination And Other Costs
Restructuring Cost And Reserve [Line Items]
Restructuring costs	(66)	631	1,287
Impairment of Property and Equipment
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 0	$ 2,821	$ 0