Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Maximum Y	Mar. 31, 2013 Minimum Y	Mar. 31, 2013 New Jersey
Income Taxes [Line Items]
Sale of net operating loss carryforwards					$ 2.4
Cash received from sale of net operating loss carryforwards					2.2
Unrecognized tax benefit	$ 2.7	$ 2.7
State income tax returns examination period, years			5	3