SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Schedule of Estimated Useful Lives of Property and Equipment

Property and equipment, including significant improvements, are recorded at cost. Repairs and maintenance costs are expensed as incurred. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, or, in the case of leasehold improvements, the lease term, if shorter.

Asset Category	Estimated Useful Lives
Buildings and leasehold improvements	3 to 39 Years
Computer equipment and capitalized software	2 to 3 Years
Furniture and other equipment	3 to 12 Years

	December 31,
	2016			2015
	(In thousands)
Property and equipment, net:
Buildings and leasehold improvements	$	247,451		$	235,545
Computer equipment and capitalized software	259,464			239,309
Furniture and other equipment	93,002			88,664
Projects in progress	13,048			18,676
Land	5,117			5,117
	618,082			587,311
Accumulated depreciation and amortization	(311,834		)	(284,494		)
Property and equipment, net	$	306,248		$	302,817

Schedule of Effect of New Accounting Pronouncement

The primary effects of the adoption of ASU No. 2016-09 on the Company’s results of operations, cash flows and earnings per share will be due to the change in the treatment of the excess tax benefit (deficiency) related to equity awards to employees upon exercise of stock options and the vesting of restricted stock units. The table below illustrates this effect.

Excess tax benefit (deficiency) of equity awards to employees upon exercise of stock options and the vesting of restricted stock units:	Accounting under current GAAP:	Accounting following adoption of ASU No. 2016-09:
Statement of operations	Treated as an increase (or decrease) to additional paid-in capital when realized (i.e., reduction of income taxes payable)	Included in the determination of the income tax provision or benefit upon option exercise or share vesting
Statement of cash flows	Treated as a financing cash flow	Treated as an operating cash flow
Calculation of fully diluted shares for the determination of earnings per share	Included as a component of the assumed proceeds in applying the treasury stock method	Excluded from the assumed proceeds in applying the treasury stock method

To illustrate the effect of ASU No. 2016-09 on the Company’s results for the year ended December 31, 2016, the table below illustrates the change in the Company’s reported results after giving pro forma effect to ASU No. 2016-09 as if it had been in effect on January 1, 2016.

	Reported results under current GAAP			Pro forma results assuming ASU No. 2016-09 had been in effect on January 1, 2016
	(In thousands, except per share data)
Net (loss) earnings	$	(16,151	)	$	33,255
Net earnings attributable to noncontrolling interests	(25,129		)	(30,024		)
Net (loss) earnings attributable to IAC shareholders	(41,280		)	3,231
Cash flows provided by operating activities attributable to continuing operations	292,377			344,141
Cash flows used in financing activities attributable to continuing operations	(451,065		)	(502,829		)
Basic (loss) earnings per share from continuing operations	$	(0.52	)	$	0.10
Fully diluted loss per share from continuing operations	$	(0.52	)	$	(0.19	)