Segment Information (Depreciation and Amortization) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 160,625	$ 159,142	$ 148,464
Digital Commerce Solutions | Global Ecommerce
Segment Reporting Information [Line Items]
Depreciation and amortization	69,676	68,385	61,046
Digital Commerce Solutions | Presort Services
Segment Reporting Information [Line Items]
Depreciation and amortization	31,769	29,440	26,838
Corporate
Segment Reporting Information [Line Items]
Depreciation and amortization	24,864	21,559	21,476
Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization	135,761	137,583	126,988
Operating Segments | Digital Commerce Solutions
Segment Reporting Information [Line Items]
Depreciation and amortization	101,445	97,825	87,884
Operating Segments | SendTech Solutions
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 34,316	$ 39,758	$ 39,104