Segment Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended				9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment reporting information profit (loss)
Revenue		$ 891,898			$ 790,125	$ 2,525,658	$ 2,373,782
Reconciliation of Segment EBIT to net income (loss):
Restructuring charges and asset impairments		(3,766)			(47,017)	(12,505)	(56,616)
Interest expense, net		(27,175)			(28,704)	(79,504)	(84,325)
Gain on sale of equity investment			$ 12,000			21,969	0
Goodwill impairment		0			0	(198,169)	0
Loss on extinguishment of debt	$ (37,000)	0			(667)	(36,987)	(667)
(Provision) benefit for income taxes		(554)			24,895	(7,540)	13,351
Income (loss) from continuing operations		10,773			5,345	(208,071)	32,112
Income (loss) from discontinued operations, net of tax		616			(8,470)	7,648	(14,199)
Net income (loss)		11,389			(3,125)	(200,423)	17,913
Operating Segments
Segment reporting information profit (loss)
EBIT		107,323			126,848	298,061	374,341
Segment Reconciling Items
Reconciliation of Segment EBIT to net income (loss):
Unallocated corporate expenses		(53,429)			(58,277)	(146,640)	(160,283)
Restructuring charges and asset impairments		(3,766)			(47,017)	(12,505)	(56,616)
Interest expense, net		(38,801)			(39,730)	(115,558)	(117,758)
Gain on sale of equity investment		0			0	11,908	0
Goodwill impairment		0			0	(198,169)	0
Loss on extinguishment of debt		0			(667)	(36,987)	(667)
Loss on dispositions		0			0	0	(17,683)
Transaction costs		0			(707)	(641)	(2,573)
(Provision) benefit for income taxes		(554)			24,895	(7,540)	13,351
Insurance claim		6,000				15,000
Commerce Services
Segment reporting information profit (loss)
Revenue from contracts with customers		537,686			410,478	1,487,309	1,222,036
Reconciliation of Segment EBIT to net income (loss):
Goodwill impairment						(198,169)
Commerce Services | Operating Segments
Segment reporting information profit (loss)
EBIT		(5,276)			(4,106)	(25,368)	(3,754)
Commerce Services | Global Ecommerce
Segment reporting information profit (loss)
Revenue from contracts with customers		409,981			278,995	1,100,757	827,568
EBIT		(19,757)			(21,793)	(68,126)	(51,969)
Reconciliation of Segment EBIT to net income (loss):
Goodwill impairment				$ (198,000)		(198,169)
Commerce Services | Presort Services
Segment reporting information profit (loss)
Revenue from contracts with customers		127,705			131,483	386,552	394,468
EBIT		14,481			17,687	42,758	48,215
Reconciliation of Segment EBIT to net income (loss):
Goodwill impairment						0
SendTech Solutions
Segment reporting information profit (loss)
Revenue from contracts with customers		354,212			379,647	1,038,349	1,151,746
Reconciliation of Segment EBIT to net income (loss):
Goodwill impairment						0
SendTech Solutions | Operating Segments
Segment reporting information profit (loss)
EBIT		$ 112,599			$ 130,954	$ 323,429	$ 378,095