Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Capital expenditures	$ 170,990	$ 160,831	$ 166,746
Small & Medium Business Solutions | North America Mailing
Segment Reporting Information [Line Items]
Capital expenditures	69,131	83,547	60,621
Small & Medium Business Solutions | International Mailing
Segment Reporting Information [Line Items]
Capital expenditures	11,982	3,163	11,196
Enterprise Business Solutions | Production Mail
Segment Reporting Information [Line Items]
Capital expenditures	2,893	1,599	3,418
Enterprise Business Solutions | Presort Services
Segment Reporting Information [Line Items]
Capital expenditures	20,860	17,537	17,096
Digital Commerce Solutions | Software Solutions
Segment Reporting Information [Line Items]
Capital expenditures	9,181	4,617	1,688
Digital Commerce Solutions | Global Ecommerce
Segment Reporting Information [Line Items]
Capital expenditures	26,810	15,647	17,321
Operating Segments
Segment Reporting Information [Line Items]
Capital expenditures	140,857	126,110	112,197
Operating Segments | Small & Medium Business Solutions
Segment Reporting Information [Line Items]
Capital expenditures	81,113	86,710	71,817
Operating Segments | Enterprise Business Solutions
Segment Reporting Information [Line Items]
Capital expenditures	23,753	19,136	20,514
Operating Segments | Digital Commerce Solutions
Segment Reporting Information [Line Items]
Capital expenditures	35,991	20,264	19,009
Operating Segments | Other
Segment Reporting Information [Line Items]
Capital expenditures	0	0	857
Unallocated amount
Segment Reporting Information [Line Items]
Capital expenditures	$ 30,133	$ 34,721	$ 54,549