Disclosures About Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2011

Disclosures About Fair Value Measurements [Abstract]

Assets And Liabilities That Are Measured At Fair Value On A Recurring Basis

		Fair Value Measurements at Reporting Date Using
	Quoted Prices in Active Markets for Identical Assets (Level  1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at December 31, 2011
	(in thousands)
Assets:
Trading securities	$	257	$	168	$	—	$	425
Commodity derivatives		—		482,075		—		482,075
Deferred compensation plan assets		39,904		—		—		39,904
Total assets	$	40,161	$	482,243	$	—	$	522,404
Liabilities:
Commodity derivatives	$	—	$	92,322	$	—	$	92,322
Interest rate derivatives		—		15,654		—		15,654
Liability Awards		9,207		—		—		9,207
Total liabilities	$	9,207	$	107,976	$	—	$	117,183

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at December 31, 2010
	(in thousands)
Assets:
Trading securities	$	316	$	151	$	—	$	467
Commodity derivatives		—		304,434		—		304,434
Interest rate derivatives		—		18,256		—		18,256
Deferred compensation plan assets		36,162		—		—		36,162
Total assets	$	36,478	$	322,841	$	—	$	359,319
Liabilities:
Commodity derivatives	$	—	$	127,311	$	9,556	$	136,867
Interest rate derivatives		—		704		—		704
Liability Awards		4,900		—		—		4,900
Total liabilities	$	4,900	$	128,015	$	9,556	$	142,471

Fair Value Measurements Using Significant Unobservable Inputs

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	Year Ended December 31, 2011
	(in thousands)
Beginning liability balance	$	(9,556	)
Fair value changes (a):
Net unrealized gains included in earnings		188
Net realized losses included in earnings		(11,803	)
Settlement payments		11,803
Transfers out of Level 3 (b)		9,368
Ending liability balance	$	—

(a) Changes in fair value are included in derivative gains (losses), net in the accompanying consolidated statements of operations.

(b) The values related to NGL swap and collar contracts were transferred from Level 3 to Level 2 as a result of the Company's ability to obtain independent market-quoted NGL data. The Company recognized the transfer between Level 3 and Level 2 at the end of the reporting period of transfer.

Fair Values Of The Company Financial Instruments

	December 31, 2011				December 31, 2010
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(in thousands)
Assets:
Commodity price derivatives	$	482,075	$	482,075	$	304,434	$	304,434
Interest rate derivatives	$	—	$	—	$	18,256	$	18,256
Trading securities	$	425	$	425	$	467	$	467
Deferred compensation plan assets	$	39,904	$	39,904	$	36,162	$	36,162
Liabilities:
Commodity price derivatives	$	92,322	$	92,322	$	136,867	$	136,867
Interest rate derivatives	$	15,654	$	15,654	$	704	$	704
Liability Awards	$	9,207	$	9,207	$	4,900	$	4,900
Pioneer credit facility	$	—	$	—	$	49,000	$	58,382
Pioneer Southwest credit facility	$	32,000	$	32,393	$	81,200	$	77,241
5.875% senior notes due 2016	$	405,388	$	488,445	$	396,880	$	475,194
6.65% senior notes due 2017	$	484,185	$	546,931	$	484,045	$	516,632
6.875% senior notes due 2018	$	449,225	$	505,688	$	449,192	$	480,969
7.50% senior notes due 2020	$	446,716	$	523,373	$	446,433	$	494,145
7.20% senior notes due 2028	$	249,928	$	269,125	$	249,925	$	259,350
2.875% convertible senior notes due 2038 (a)	$	461,463	$	739,630	$	444,994	$	728,400

(a) The fair value of the 2.875% convertible senior notes include the fair value of the conversion privilege.