Segment Information (EBIT) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciling items:
Restructuring charges			$ (61,585)	$ (18,715)	$ (19,003)
Goodwill impairment	$ (220,000)	$ (119,000)	(339,184)	0	0
Gain on sale of assets			0	14,372	1,434
Gain on sale of businesses, including transaction costs			0	12,205	10,201
Gain (loss) on debt redemption/refinancing			3,064	(4,993)	(56,209)
Benefit (provision) for income taxes			20,875	(2,940)	10,922
(Loss) income from continuing operations			(385,627)	36,940	3,507
Loss from discontinued operations, net of tax			0	0	(4,858)
Net (loss) income			(385,627)	36,940	(1,351)
Operating Segments
Segment Reporting Information [Line Items]
EBIT			382,526	383,031	410,463
Operating Segments | Global Ecommerce
Segment Reporting Information [Line Items]
EBIT			(133,733)	(100,308)	(98,673)
Reconciling items:
Goodwill impairment	$ (220,000)	$ (119,000)	(339,184)
Operating Segments | Presort Services
Segment Reporting Information [Line Items]
EBIT			110,912	82,430	79,721
Reconciling items:
Goodwill impairment			0
Operating Segments | SendTech Solutions
Segment Reporting Information [Line Items]
EBIT			405,347	400,909	429,415
Reconciling items:
Goodwill impairment			0
Reconciling Items
Reconciling items:
Interest, net			(163,726)	(141,769)	(143,945)
Unallocated corporate expenses			(210,931)	(204,251)	(207,774)
Restructuring charges			(61,585)	(18,715)	(19,003)
Goodwill impairment			(339,184)	0	0
Gain on sale of assets			0	14,372	1,434
Gain on sale of businesses, including transaction costs			0	12,205	7,619
Gain (loss) on debt redemption/refinancing			3,064	(4,993)	(56,209)
Proxy solicitation fees			(10,905)	0	0
Foreign currency loss on intercompany loans			$ (5,761)	$ 0	$ 0