Goodwill, Customer Relationships and Other Intangible Assets - Rollforward of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Goodwill [Roll Forward]
As of December 31, 2018		$ 28,031,000		$ 28,031,000
January 2019 reorganization				0
Effect of foreign currency rate change				2,000
Impairment of goodwill	$ 0	(6,500,000)	$ 0	(6,506,000)	$ 0
As of June 30, 2019	21,527,000			21,527,000
International and Global Accounts
Goodwill [Roll Forward]
As of December 31, 2018		3,595,000		3,595,000
January 2019 reorganization				0
Effect of foreign currency rate change				2,000
Impairment of goodwill				(934,000)
As of June 30, 2019	2,663,000			2,663,000
Enterprise
Goodwill [Roll Forward]
As of December 31, 2018		5,222,000		5,222,000
January 2019 reorganization				987,000
Effect of foreign currency rate change				0
Impairment of goodwill				(1,471,000)
As of June 30, 2019	4,738,000			4,738,000
Small and Medium Business
Goodwill [Roll Forward]
As of December 31, 2018		5,193,000		5,193,000
January 2019 reorganization				(1,038,000)
Effect of foreign currency rate change				0
Impairment of goodwill				(896,000)
As of June 30, 2019	3,259,000			3,259,000
Wholesale
Goodwill [Roll Forward]
As of December 31, 2018		6,437,000		6,437,000
January 2019 reorganization				395,000
Effect of foreign currency rate change				0
Impairment of goodwill				(3,019,000)
As of June 30, 2019	3,813,000			3,813,000
Consumer
Goodwill [Roll Forward]
As of December 31, 2018		$ 7,584,000		7,584,000
January 2019 reorganization				(344,000)
Effect of foreign currency rate change				0
Impairment of goodwill				(186,000)
As of June 30, 2019	$ 7,054,000			$ 7,054,000