CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Agency revenues	$ 5,845,802pcln_AgencyRevenue	$ 4,410,689pcln_AgencyRevenue	$ 3,142,815pcln_AgencyRevenue
Merchant revenues	2,186,054pcln_MerchantRevenue	2,211,474pcln_MerchantRevenue	2,104,752pcln_MerchantRevenue
Advertising and other revenues	410,115us-gaap_OtherSalesRevenueNet	171,143us-gaap_OtherSalesRevenueNet	13,389us-gaap_OtherSalesRevenueNet
Total revenues	8,441,971us-gaap_SalesRevenueNet	6,793,306us-gaap_SalesRevenueNet	5,260,956us-gaap_SalesRevenueNet
Cost of revenues	857,841us-gaap_CostOfGoodsAndServicesSold	1,077,420us-gaap_CostOfGoodsAndServicesSold	1,177,275us-gaap_CostOfGoodsAndServicesSold
Gross profit	7,584,130us-gaap_GrossProfit	5,715,886us-gaap_GrossProfit	4,083,681us-gaap_GrossProfit
Operating expenses:
Advertising — Online	2,360,221pcln_OnlineAdvertisingExpense	1,798,645pcln_OnlineAdvertisingExpense	1,273,637pcln_OnlineAdvertisingExpense
Advertising — Offline	231,309pcln_OfflineAdvertisingExpense	127,459pcln_OfflineAdvertisingExpense	35,492pcln_OfflineAdvertisingExpense
Sales and marketing	310,910us-gaap_SellingAndMarketingExpense	235,817us-gaap_SellingAndMarketingExpense	195,934us-gaap_SellingAndMarketingExpense
Personnel, including stock-based compensation of $186,425, $140,526 and $71,565, respectively	950,191us-gaap_LaborAndRelatedExpense	698,692us-gaap_LaborAndRelatedExpense	466,828us-gaap_LaborAndRelatedExpense
General and administrative	352,869us-gaap_GeneralAndAdministrativeExpense	252,994us-gaap_GeneralAndAdministrativeExpense	173,171us-gaap_GeneralAndAdministrativeExpense
Information technology	97,498	71,890	43,685
Depreciation and amortization	207,820us-gaap_DepreciationAndAmortization	117,975us-gaap_DepreciationAndAmortization	65,141us-gaap_DepreciationAndAmortization
Total operating expenses	4,510,818us-gaap_OperatingExpenses	3,303,472us-gaap_OperatingExpenses	2,253,888us-gaap_OperatingExpenses
Operating income	3,073,312us-gaap_OperatingIncomeLoss	2,412,414us-gaap_OperatingIncomeLoss	1,829,793us-gaap_OperatingIncomeLoss
Other income (expense):
Interest income	13,933us-gaap_InvestmentIncomeInterest	4,167us-gaap_InvestmentIncomeInterest	3,860us-gaap_InvestmentIncomeInterest
Interest expense	(88,353)us-gaap_InterestExpense	(83,289)us-gaap_InterestExpense	(62,064)us-gaap_InterestExpense
Foreign currency transactions and other	(9,444)	(36,755)	(9,720)
Total other income (expense)	(83,864)us-gaap_NonoperatingIncomeExpense	(115,877)us-gaap_NonoperatingIncomeExpense	(67,924)us-gaap_NonoperatingIncomeExpense
Earnings before income taxes	2,989,448	2,296,537	1,761,869
Income tax expense	567,695us-gaap_IncomeTaxExpenseBenefit	403,739us-gaap_IncomeTaxExpenseBenefit	337,832us-gaap_IncomeTaxExpenseBenefit
Net income	2,421,753us-gaap_ProfitLoss	1,892,798us-gaap_ProfitLoss	1,424,037us-gaap_ProfitLoss
Less: net income attributable to noncontrolling interests	0	135	4,471
Net income applicable to common stockholders	$ 2,421,753	$ 1,892,663	$ 1,419,566
Net income applicable to common stockholders per basic common share	$ 46.30us-gaap_EarningsPerShareBasic	$ 37.17us-gaap_EarningsPerShareBasic	$ 28.48us-gaap_EarningsPerShareBasic
Weighted average number of basic common shares outstanding	52,301	50,924	49,840
Net income applicable to common stockholders per diluted common share	$ 45.67us-gaap_EarningsPerShareDiluted	$ 36.11us-gaap_EarningsPerShareDiluted	$ 27.66us-gaap_EarningsPerShareDiluted
Weighted average number of diluted common shares outstanding	53,023	52,413	51,326

Agency revenues are derived from travel related transactions where the entity is not the merchant of record and where the prices of services are determined by third parties. Agency revenues include travel commissions, customer processing fees and GDS reservation booking fees related to certain of the services listed above and are reported at the net amounts received, without any associated cost of revenue.

No definition available.