Restructuring Charges (Details Textual) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Restructuring Charges (Textual) [Abstract]
Restructuring Reserve	$ 7,224	$ 6,950	$ 7,996	$ 11,655
Marketing & Events Group [Member] | Severance & Employee Benefits [Member]
Restructuring Charges (Textual) [Abstract]
Restructuring Reserve	720	831	1,106	2,333
Marketing & Events Group [Member] | Facilities [Member]
Restructuring Charges (Textual) [Abstract]
Restructuring Reserve	5,571	4,819	5,051	6,295
Other Restructuring [Member] | Severance & Employee Benefits [Member]
Restructuring Charges (Textual) [Abstract]
Restructuring Reserve		24	197
Other Restructuring [Member] | Facilities [Member]
Restructuring Charges (Textual) [Abstract]
Restructuring Reserve	$ 933	$ 1,276	$ 1,642	$ 3,027