Impact of Tax Correction to Consolidated Statements of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other income, net	$ (2,400)	$ 122	$ (3,274)	$ 1,279
Income before income tax provision	(29,403)	10,283	(25,024)	16,804
Income tax provision	2,102	4,565	3,880	7,716
Net income	(31,505)	5,718	(28,904)	9,088
Net income attributable to Quest Software, Inc.	(31,391)	5,718	(28,723)	9,088
Basic	$ (0.37)	$ 0.06	$ (0.34)	$ 0.10
Diluted	$ (0.36)	$ 0.06	$ (0.33)	$ 0.10
As Previously Reported
Other income, net		573		1,843
Income before income tax provision		10,734		17,368
Income tax provision		4,404		7,410
Net income		6,330		9,958
Net income attributable to Quest Software, Inc.		6,330		9,958
Basic		$ 0.07		$ 0.11
Diluted		$ 0.07		$ 0.11
As Corrected
Other income, net		122		1,279
Income before income tax provision		10,283		16,804
Income tax provision		4,565		7,716
Net income		5,718		9,088
Net income attributable to Quest Software, Inc.		5,718		9,088
Basic		$ 0.06		$ 0.10
Diluted		$ 0.06		$ 0.10
Increase/(Decrease)
Other income, net		(451)		(564)
Income before income tax provision		(451)		(564)
Income tax provision		161		306
Net income		(612)		(870)
Net income attributable to Quest Software, Inc.		$ (612)		$ (870)
Basic		$ (0.01)		$ (0.01)
Diluted		$ (0.01)		$ (0.01)