Restructuring Activities - Restructuring and Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 4,991	$ 0
Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3,281	7,788
Customer database build write off | Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,845	4,036
Contract termination fee | Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	2,100
Severance | Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	496	644
Facility, asset impairment and other expense | Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 940	$ 1,008