Commitments And Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Line Items]
December 31, 2012	$ 30,545,000
December 31, 2013	28,580,000
December 31, 2014	23,443,000
December 31, 2015	21,413,000
December 31, 2016	19,661,000
Thereafter	110,072,000
Total	233,714,000
Office space and equipment rent expense	55,200,000	47,900,000	51,400,000
Deferred rent liabilties	7,100,000	6,900,000
Building [Member]
Operating Leased Assets [Line Items]
December 31, 2012	29,584,000
December 31, 2013	27,813,000
December 31, 2014	23,415,000
December 31, 2015	21,404,000
December 31, 2016	19,661,000
Thereafter	110,072,000
Total	231,949,000
Equipment [Member]
Operating Leased Assets [Line Items]
December 31, 2012	961,000
December 31, 2013	767,000
December 31, 2014	28,000
December 31, 2015	9,000
December 31, 2016	0
Thereafter	0
Total	$ 1,765,000