Restructuring Charges - Reconciliation of Beginning and Ending Liability Balances by Major Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			$ 1,944
Restructuring charges	$ 1,069	$ 1,365	1,285	$ 1,576
Restructuring liabilities			(1,669)	(3,001)
Adjustment to liability			(144)
Closing Balance	1,416		1,416
Marketing & Events Group
Reconciliation of beginning and ending liability balances by major restructuring activity
Restructuring charges	383	$ 244	471	$ 206
Marketing & Events Group | Severance & Employee Benefits
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			543
Restructuring charges			643
Restructuring liabilities			(891)
Adjustment to liability			0
Closing Balance	295		295
Marketing & Events Group | Facilities
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			1,161
Restructuring charges			98
Restructuring liabilities			(235)
Adjustment to liability			0
Closing Balance	1,024		1,024
Other Restructuring | Severance & Employee Benefits
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			240
Restructuring charges			544
Restructuring liabilities			(543)
Adjustment to liability			(144)
Closing Balance	$ 97		$ 97