OTHER ASSETS (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	3 Months Ended	1 Months Ended
Jun. 30, 2010	Jun. 30, 2010	Mar. 31, 2010 1.25% Convertible Senior Notes due March 2015 Years	Sep. 30, 2007 Revolving credit facility Years	Sep. 30, 2006 0.75% Convertible Senior Notes due September 2013 Years	Jun. 30, 2011 0.75% Convertible Senior Notes due September 2013	Dec. 31, 2006 0.75% Convertible Senior Notes due September 2013
Debt Instrument
Aggregate principal amount			$ 575.0	$ 175.0	$ 172.5		$ 172.5
Interest rate stated percentage (as a percent)			1.25%			0.75%	0.75%
Deferred debt issuance cost, amortization period (in years)			5	5	7
Unamortized debt issuance costs written off to interest expense related to early conversion of convertible debt	$ 0.4	$ 1.0

Amortization period for debt issuance costs incurred.

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Namespace Prefix:	pcln
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Balance Type:	na
Period Type:	duration

- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28

+ Details

Name:	us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration