Stock-Based Compensation Expense, Income Tax Benefits Related to Stock-Based Compensation and Excess Tax Benefits (Provision) Recorded by Company (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation (expense)	$ (1,250)	[1]	$ (798)	[1]	$ (3,111)	[1]	$ (3,411)	[1]
Income taxes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	438	[2]	311	[2]	1,089	[2]	1,330	[2]
Additional Paid-in Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit (deficiency) from stock-based compensation			$ (87)	[3]	$ (278)	[3]	$ (52)	[3]

[1] Included in "General and administrative" costs in the accompanying Condensed Consolidated Statements of Operations.

[2] Included in "Income taxes" in the accompanying Condensed Consolidated Statements of Operations.

[3] Included in "Additional paid-in capital" in the accompanying Condensed Consolidated Statements of Changes in Shareholder's Equity.