Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Capital expenditures	$ 191,444	$ 168,097	$ 159,232
Commerce Services | Global Ecommerce
Segment Reporting Information [Line Items]
Capital expenditures	46,117	26,810	15,647
Commerce Services | Presort Services
Segment Reporting Information [Line Items]
Capital expenditures	42,532	20,860	17,537
SMB Solutions | North America Mailing
Segment Reporting Information [Line Items]
Capital expenditures	61,458	69,131	83,547
SMB Solutions | International Mailing
Segment Reporting Information [Line Items]
Capital expenditures	10,701	11,982	3,163
Operating Segments
Segment Reporting Information [Line Items]
Capital expenditures	165,059	137,964	124,511
Operating Segments | Commerce Services
Segment Reporting Information [Line Items]
Capital expenditures	88,649	47,670	33,184
Operating Segments | SMB Solutions
Segment Reporting Information [Line Items]
Capital expenditures	72,159	81,113	86,710
Operating Segments | Software Solutions
Segment Reporting Information [Line Items]
Capital expenditures	4,251	9,181	4,617
Unallocated amount
Segment Reporting Information [Line Items]
Capital expenditures	$ 26,385	$ 30,133	$ 34,721