Amounts Charged To Expense For Stock-based Compensation (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	$ 2,075		$ 602		$ 3,321		$ 1,669
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	1,974		531		3,186		1,479
Directors restricted stock grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	60	[1]	60	[1]	120	[1]	120	[1]
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	41		68		15		123
Stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation			$ (57)	[2]			$ (53)	[2]

[1] Relates to non-employee directors serving on the Parent Company's Board of Directors, all of whom have been elected by the Company's stockholders, as well as non-employee directors serving on NUAL's Board of Directors.

[2] All outstanding stock appreciation rights were exercised during 2011. The Company has no current plans to issue stock appreciation rights under the 2005 Amended and Restated Stock Incentive Plan.