SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 USD ($)	Nov. 25, 2015 EUR (€)	Mar. 03, 2015 EUR (€)	Dec. 31, 2014 EUR (€)	Dec. 31, 2014 USD ($)	Sep. 23, 2014 EUR (€)
Accounting Policies [Abstract]
Customer loyalty program liability, current					$ 71,100				$ 71,100
Accrued online advertising liabilities					188,200				164,000
Accrued compensation liabilities					186,100				159,000
New Accounting Pronouncement, Early Adoption [Line Items]
Deferred income taxes									0
Total current assets					3,553,237				5,113,620
Other assets					118,656				41,516
Total assets					17,420,575				14,770,977
Accrued expenses and other current liabilities					681,587				599,515
Convertible debt					0				37,150
Total current liabilities					1,439,310				1,378,703
Deferred income taxes					892,576				897,848
Long-term debt					6,158,443				3,823,870
Total liabilities					$ 8,625,106				6,203,954
Gross proceeds from long-term debt		$ 2,300,000	$ 1,000,000
2.15% Senior Notes Due November 2022 [Member]
Accounting Policies [Abstract]
Senior notes face amount | €				€ 750		€ 750
New Accounting Pronouncement, Early Adoption [Line Items]
Payments of debt issuance costs	$ (3,700)
1.8% Senior Notes Due March 2027 [Member]
Accounting Policies [Abstract]
Senior notes face amount | €				1,000			€ 1,000
New Accounting Pronouncement, Early Adoption [Line Items]
Payments of debt issuance costs	(6,300)
2.375% Senior Notes Due September 2024
Accounting Policies [Abstract]
Senior notes face amount | €				€ 1,000				€ 1,000		€ 1,000
New Accounting Pronouncement, Early Adoption [Line Items]
Payments of debt issuance costs		(6,500)
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2015-17 [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Deferred income taxes									(153,754)
Total current assets									(153,754)
Other assets									10,099
Total assets									(143,655)
Accrued expenses and other current liabilities									(1,243)
Total current liabilities									(1,243)
Deferred income taxes									(142,412)
Total liabilities									(143,655)
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Other assets									(25,931)
Total assets									(25,931)
Convertible debt									(45)
Total current liabilities									(45)
Long-term debt									(25,886)
Total liabilities									(25,931)
Scenario, Previously Reported [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Deferred income taxes									153,754
Total current assets									5,267,374
Other assets									57,348
Total assets									14,940,563
Accrued expenses and other current liabilities									600,758
Convertible debt									37,195
Total current liabilities									1,379,991
Deferred income taxes									1,040,260
Long-term debt									3,849,756
Total liabilities									$ 6,373,540
Debt Issuance Costs Excluding Revolving Credit Facility [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Payments of debt issuance costs		(17,500)	$ (1,000)
Software Development [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Additions to Capitalized Website Development	$ 44,200	$ 20,900