Goodwill and Other Intangibles (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Goodwill
Balance at the beginning of the period				$ 274,292	$ 468,479
Impairment losses	(274,285)	(4,282)	(225,035)	(274,285)	(229,317)	(5,375)
Currency translation adjustment				(7)	(11)
Balance at the end of the period		274,292			274,292	468,479
Ross Smith Energy Group Ltd. ("RSEG")
Goodwill
Acquisition					30,715
Majestic Research Corp.
Goodwill
ITG Investment Research price adjustment					144
U.S. Operations
Goodwill
Balance at the beginning of the period				245,105	439,294
Impairment losses	(274,300)		(225,000)	(245,103)	(225,035)
Currency translation adjustment				(2)	(13)
Balance at the end of the period		245,105	470,100		245,105
U.S. Operations | Ross Smith Energy Group Ltd. ("RSEG")
Goodwill
Acquisition					30,715
U.S. Operations | Majestic Research Corp.
Goodwill
ITG Investment Research price adjustment					144
European Operations
Goodwill
Balance at the beginning of the period				28,486	28,484
Impairment losses				(28,481)
Currency translation adjustment				(5)	2
Balance at the end of the period		28,486			28,486
Asia Pacific Operations
Goodwill
Balance at the beginning of the period				701
Impairment losses				(701)
Balance at the end of the period						$ 701