Restructuring Reserves (Details) (USD $)	12 Months Ended			24 Months Ended	36 Months Ended	12 Months Ended		24 Months Ended	60 Months Ended		24 Months Ended	12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010 Employees	Dec. 31, 2009 Employees	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2011 Employee severance and termination benefits [Member]	Dec. 31, 2009 Employee severance and termination benefits [Member]	Dec. 31, 2011 Employee severance and termination benefits [Member]	Dec. 31, 2010 Employee severance and termination benefits [Member]	Dec. 31, 2006 Employee severance and termination benefits [Member]	Dec. 31, 2011 Office closures [Member]	Dec. 31, 2011 2010 Restructuring Plan [Member]	Dec. 31, 2010 2010 Restructuring Plan [Member]	Jan. 28, 2010 2010 Restructuring Plan [Member]	Dec. 31, 2011 2010 Restructuring Plan [Member] Employee severance and termination benefits [Member]	Dec. 31, 2010 2010 Restructuring Plan [Member] Employee severance and termination benefits [Member]	Jan. 28, 2010 2010 Restructuring Plan [Member] Employee severance and termination benefits [Member]	Dec. 31, 2011 2010 Restructuring Plan [Member] Office closures [Member]	Dec. 31, 2010 2010 Restructuring Plan [Member] Office closures [Member]	Jan. 28, 2010 2010 Restructuring Plan [Member] Office closures [Member]	Dec. 31, 2011 2009 Restructuring Plan [Member]	Dec. 31, 2010 2009 Restructuring Plan [Member]	Dec. 31, 2009 2009 Restructuring Plan [Member]	Dec. 31, 2011 2009 Restructuring Plan [Member] Employee severance and termination benefits [Member]	Dec. 31, 2010 2009 Restructuring Plan [Member] Employee severance and termination benefits [Member]	Dec. 31, 2011 2009 Restructuring Plan [Member] Office closures [Member]	Dec. 31, 2010 2009 Restructuring Plan [Member] Office closures [Member]
Restructuring Reserve [Roll Forward]
Initial reserve						$ 0				$ 3,607,000		$ 4,250,000		$ 19,478,000	$ 941,000		$ 14,098,000	$ 3,309,000		$ 5,380,000	$ 105,000	$ 6,486,000		$ 105,000	$ 6,486,000	$ 0	$ 0
Adjustments to reserves						0			(840,000)			1,615,000			826,000			789,000			9,000	(63,000)		9,000	(63,000)	0	0
Cash charges						0			2,842,000			2,636,000	15,006,000		1,744,000	13,246,000		892,000	1,760,000		111,000	6,320,000		111,000	6,320,000	0	0
Non - Cash Settlements												(620,000)	(376,000)		0	0		(620,000)	(376,000)
Impact of changes in exchange rates						0			75,000			(11,000)	154,000		(16,000)	89,000		5,000	65,000		(3,000)	2,000		(3,000)	2,000	0	0
Reserve balance	1,781,000			1,781,000	1,781,000	0		0	0	3,607,000		2,598,000	4,250,000	19,478,000	7,000	941,000	14,098,000	2,591,000	3,309,000	5,380,000	0	105,000	6,486,000	0	105,000	0	0
Restructuring charges	1,922,000	20,931,000	6,865,000					14,900,000			6,200,000	1,615,000	19,478,000										6,500,000
Number of positions eliminated		200	86
Restructuring charges that have been paid				17,600,000	6,400,000		2,000,000
Restructuring reserve included in accrued expenses and other current liabilities	1,800,000			1,800,000	1,800,000
Restructuring reserve included in accrued exit and disposal obligations	$ 800,000			$ 800,000	$ 800,000