Impact of Tax Correction to Consolidated Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Deferred income taxes, net - current	$ 21,382	$ 21,647
Total current assets	462,241	498,068
Total assets	1,651,495	1,699,518
Income taxes payable - current	8,415	14,482
Total current liabilities	555,182	605,583
Total liabilities	756,994	809,984
Retained earnings	304,334	333,057
Total Quest Software Inc. stockholders' equity	859,734	854,585
Total equity	872,501	867,534
Total liabilities and equity	1,651,495	1,699,518
As Previously Reported
Deferred income taxes, net - current		19,780
Total current assets		496,201
Total assets		1,697,651
Total current liabilities		591,101
Total liabilities		795,502
Retained earnings		345,672
Total Quest Software Inc. stockholders' equity		867,200
Total equity		880,149
Total liabilities and equity		1,697,651
As Corrected
Deferred income taxes, net - current		21,647
Total current assets		498,068
Total assets		1,699,518
Income taxes payable - current		14,482
Total current liabilities		605,583
Total liabilities		809,984
Retained earnings		333,057
Total Quest Software Inc. stockholders' equity		854,585
Total equity		867,534
Total liabilities and equity		1,699,518
Increase/(Decrease)
Deferred income taxes, net - current		1,867
Total current assets		1,867
Total assets		1,867
Income taxes payable - current		14,482
Total current liabilities		14,482
Total liabilities		14,482
Retained earnings		(12,615)
Total Quest Software Inc. stockholders' equity		(12,615)
Total equity		(12,615)
Total liabilities and equity		$ 1,867