Business Combinations and Divestiture (Narrative) (Details) - USD ($) $ in Thousands		1 Months Ended				12 Months Ended
	May. 01, 2015	Jan. 31, 2016	Oct. 31, 2015	Jun. 30, 2015	May. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Purchase price						$ 393,695	$ 0	$ 0
Sale price of business						289,211	102,392	389,680
Gain on sale of business						105,826	28,151	$ (42,450)
Imagitas
Business Acquisition [Line Items]
Sale price of business					$ 292,000
Gain on sale of business					$ 111,000
Borderfree
Business Acquisition [Line Items]
Percentage of business acquired				100.00%
Purchase price				$ 381,000
Cash acquired				92,000
Revenues						63,000
Pro forma revenues						$ 47,000	$ 125,000
Borderfree | Selling, general and administrative expense
Business Acquisition [Line Items]
Accelerated stock-based compensation expense				10,000
Borderfree | Other (Income) Expense, Net
Business Acquisition [Line Items]
Acquisition-related costs				$ 8,000
Zip Mail
Business Acquisition [Line Items]
Payment to acquire business			$ 6,000
Additional payments to acquire business			$ 1,000
Real Time Content
Business Acquisition [Line Items]
Payment to acquire business	$ 6,000
Subsequent Event | Enroute Systems Corporation
Business Acquisition [Line Items]
Payment to acquire business		$ 14,000