Segment Information (Net (Loss) Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reconciliation of adjusted segment EBIT to net (loss) income:
Restructuring charges	$ (22,443)	$ (4,224)	$ (26,042)	$ (8,408)
Interest expense, net	(22,920)	(21,007)	(45,262)	(43,131)
Goodwill impairment	(118,599)	0	(118,599)	0
Gain (loss) on debt redemption/refinancing	228		3,064	(4,993)
Gain on sale of assets	0		0	14,372
Loss on sale of businesses, including transaction costs	0		0	2,522
Benefit for income taxes	9,415	7,026	12,665	2,823
Net (loss) income	(141,535)	4,336	(149,272)	25,157
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBIT	79,794	79,591	169,164	190,102
Segment Reconciling Items
Reconciliation of adjusted segment EBIT to net (loss) income:
Unallocated corporate expenses	(47,709)	(40,761)	(104,058)	(98,595)
Restructuring charges	(22,443)	(4,224)	(26,042)	(8,408)
Interest expense, net	(37,683)	(33,540)	(74,561)	(67,266)
Proxy solicitation fees	(4,538)	0	(10,905)	0
Goodwill impairment	(118,599)	0	(118,599)	0
Gain (loss) on debt redemption/refinancing	228	0	3,064	(4,993)
Gain on sale of assets	0	0	0	14,372
Loss on sale of businesses, including transaction costs	0	(3,756)	0	(2,878)
Benefit for income taxes	9,415	7,026	12,665	2,823
Global Ecommerce
Segment Reporting Information [Line Items]
Adjusted EBIT	(38,115)	(28,825)	(72,321)	(42,521)
Reconciliation of adjusted segment EBIT to net (loss) income:
Goodwill impairment			(118,599)
Presort Services
Segment Reporting Information [Line Items]
Adjusted EBIT	20,429	12,851	47,334	32,483
Reconciliation of adjusted segment EBIT to net (loss) income:
Goodwill impairment			0
SendTech Solutions
Segment Reporting Information [Line Items]
Adjusted EBIT	$ 97,480	$ 95,565	194,151	$ 200,140
Reconciliation of adjusted segment EBIT to net (loss) income:
Goodwill impairment			$ 0