Stock-based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total number of shares authorized for grant before amendment		10,250,000
Total number of shares authorized for grant after amendment		15,250,000
Options outstanding, aggregate intrinsic value	$ 17,900,000
Options outstanding, weighted-average remaining contractual term	5.3
Options exercisable, aggregate intrinsic value	14,600,000
Options exercisable, weighted-average remaining contractual term	4.8
Outstanding non-vested options	1,003,660
Restricted Stock Awards
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Outstanding non-vested restricted stock	1,100,000
Performance Unit Awards 2009
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	The performance period for the 2009 Performance Units is the period from April 1, 2009 through March 31, 2012, but can extend through March 31, 2014 in certain circumstances.
Award description	Generally, the recipients will receive a base payment if the Company's total shareholder return is positive and, when compared to the peer group, is at or above the 25th percentile but less than the 50th percentile, two times the base if at or above the 50th percentile but less than the 75th percentile, and four times the base if at the 75th percentile or higher.
Base payment	1,700,000
Pro-rated obligation	3,600,000
Compensation expense	1,300,000	1,500,000	859,000.0
Performance Unit Awards 2009 | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2012
Performance Unit Awards 2009 | Maximum | Certain Circumstances
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2014
Performance Unit Awards 2009 | Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	April 1, 2009
Performance Unit Awards 2010
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	The performance period for the 2010 Performance Units is the period from April 1, 2010 through March 31, 2013, but can extend through March 31, 2015 in certain circumstances.
Award description	Generally, the recipients will receive a base number of shares if the Company’s total shareholder return is positive and, when compared to the peer group, is at the 25th percentile, two times the base if at the 50th percentile, and four times the base if at the 75th percentile or higher. The grant of shares when achievement is between the 25th and 75th percentile will be determined on a pro-rata basis.
Compensation expense	1,000,000	779,000
Base number of shares	89,375
Grant date fair value	3,100,000
Performance Unit Awards 2010 | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2013
Performance Unit Awards 2010 | Maximum | Certain Circumstances
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2015
Performance Unit Awards 2010 | Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	April 1, 2010
Performance Unit Awards 2011
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	The performance period for the 2011 Performance Units is the period from April 1, 2011 through March 31, 2014, but can extend through March 31, 2016 in certain circumstances.
Award description	Generally, the recipients will receive a base number of shares if the Company’s total shareholder return is positive and, when compared to the peer group, is at the 25th percentile, two times the base if at the 50th percentile, and four times the base if at the 75th percentile or higher. The grant of shares when achievement is between the 25th and 75th percentile will be determined on a pro-rata basis.
Compensation expense	1,400,000
Base number of shares	72,188
Grant date fair value	$ 5,600,000
Performance Unit Awards 2011 | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2014
Performance Unit Awards 2011 | Maximum | Certain Circumstances
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	March 31, 2016
Performance Unit Awards 2011 | Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Performance period	April 1, 2011
Patterson-UTI Energy, Inc. 2005 Long-Term Incentive Plan, as amended
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total number of shares authorized for grant after amendment	15,250,000
Patterson-UTI Energy, Inc. 2005 Long-Term Incentive Plan, as amended | Non Employee Director
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	1 year
Patterson-UTI Energy, Inc. 2005 Long-Term Incentive Plan, as amended | Employees
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	3 years
Patterson-UTI Energy, Inc. 2005 Long-Term Incentive Plan, as amended | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Option term	10 years
Patterson-UTI Energy, Inc. Amended and Restated 1997 Long-Term Incentive Plan, as amended ("1997 Plan") | Restricted Stock Awards
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	4 years
Patterson-UTI Energy, Inc. Amended and Restated 1997 Long-Term Incentive Plan, as amended ("1997 Plan") | Employee Stock Option | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	5 years
Option term	10 years
Patterson-UTI Energy, Inc. Amended and Restated 1997 Long-Term Incentive Plan, as amended ("1997 Plan") | Employee Stock Option | Minimum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	3 years
Amended and Restated Patterson-UTI Energy, Inc. 2001 Long-Term Incentive Plan ("2001 Plan") | Employee Stock Option
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Awards vesting period	5 years
Amended and Restated Patterson-UTI Energy, Inc. 2001 Long-Term Incentive Plan ("2001 Plan") | Employee Stock Option | Maximum
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Option term	10 years