Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Capital expenditures	$ 104,987	$ 137,253	$ 137,810
Commerce Services | Global Ecommerce
Segment Reporting Information [Line Items]
Capital expenditures	46,427	53,374	46,073
Commerce Services | Presort Services
Segment Reporting Information [Line Items]
Capital expenditures	15,795	27,394	42,531
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	13,942	24,209	24,558
Operating Segments
Segment Reporting Information [Line Items]
Capital expenditures	91,045	113,044	113,252
Operating Segments | Commerce Services
Segment Reporting Information [Line Items]
Capital expenditures	62,222	80,768	88,604
Operating Segments | SendTech Solutions
Segment Reporting Information [Line Items]
Capital expenditures	$ 28,823	$ 32,276	$ 24,648