Income Taxes - Components of Deferred Income Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Net operating loss carryforwards, or NOLs	$ 24,067	$ 27,212
Worker's compensation and other current accruals (1)	16,929	15,487
Disputed receivables reserved	956	6
Deferred compensation	9,051	4,504
Foreign contribution taxes	6,780	5,615
Mobilization	4,736
Nonqualified stock options and SARs	8,698	7,538
Other	1,640	2,212
Total deferred tax assets	72,857	62,574
Valuation allowance for NOLs	(22,876)	(26,353)
Net deferred tax assets	49,981	36,221
Deferred tax liabilities:
Depreciation	(526,606)	(558,915)
Unbilled revenue	(5,649)	(3,216)
Mobilization		(3,939)
Undistributed earnings of foreign subsidiaries	(24)	(24)
Other	(29)	(141)
Total deferred tax liabilities	(532,308)	(566,235)
Net deferred tax liability	$ (482,327)	$ (530,014)