Restructuring Charges - Reconciliation of Beginning and Ending Liability Balances by Major Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			$ 1,944
Restructuring charges	$ 257	$ 238	1,542	$ 1,814
Restructuring liabilities			(1,888)	(4,268)
Adjustment to liability			(144)
Closing Balance	1,454		1,454
Marketing & Events Group
Reconciliation of beginning and ending liability balances by major restructuring activity
Restructuring charges	25	$ 186	496	$ 392
Marketing & Events Group | Severance & Employee Benefits
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			543
Restructuring charges			882
Restructuring liabilities			(1,036)
Adjustment to liability			0
Closing Balance	389		389
Marketing & Events Group | Facilities
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			1,161
Restructuring charges			98
Restructuring liabilities			(291)
Adjustment to liability			0
Closing Balance	968		968
Other Restructuring | Severance & Employee Benefits
Reconciliation of beginning and ending liability balances by major restructuring activity
Beginning Balance			240
Restructuring charges			562
Restructuring liabilities			(561)
Adjustment to liability			(144)
Closing Balance	$ 97		$ 97