Discontinued operations - Disposal of Discontinued Activity (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2015
Results of operations of the Advertising Business [Line Items]
Pretax loss from operations of discontinued operations	$ (1,171)	$ (1,262)
Loss on disposal of discontinued operations	(41,471)	(41,471)
Income tax expenses	127	127
Less: Non-controlling interests	(1,280)	(1,297)
Net loss from discontinued operations attributable to IDI	(41,489)	(41,563)
Advertising Business [Member]
Results of operations of the Advertising Business [Line Items]
Revenue	162	171
Pretax loss from operations of discontinued operations	(1,171)	(1,262)
Loss on disposal of discontinued operations	(41,471)	(41,471)
Income tax expenses	127	127
Less: Non-controlling interests	(1,280)	(1,297)
Net loss from discontinued operations attributable to IDI	$ (41,489)	$ (41,563)

Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

+ References + Details

- Definition

Amount after tax of income (loss) from a discontinued operation attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=65878427&loc=d3e1012-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721523-107759

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=68079674&loc=SL4569616-111683

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=68079674&loc=SL4568447-111683

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
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-Section 45
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721525-107759

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=65878427&loc=d3e957-107759

+ Details

- Definition

Amount after tax of income (loss) from a discontinued operation attributable to the parent. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

+ References + Details