Amounts Charged to Expense for Stock-based Compensation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	$ 3,914		$ 7,852		$ 460
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	3,369		7,380		139
Directors restricted stock grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	413	[1]	390	[1]	248	[1]
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	132		82		173
Stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation					$ (100)	[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.