Stock Based Compensation (Detail) - Stock option activity (Stock Options [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock Options [Member]
Outstanding Number of Shares	1,814,956	2,093,654	1,640,624
Outstanding Weighted Average Exercise Price (in Dollars per share)	$ 6.39	$ 8.91	$ 11.71
Outstanding Weighted Average Remaining Contractual Term	6 years 146 days	7 years 36 days	7 years 219 days	6 years 292 days
Exercisable at December 31, 2012	6 years 255 days
Exercised			(12,500)
Exercised (in Dollars per share)			$ 9.22
Lapsed Number of Shares		(566,000)	(70,000)
Lapsed Weighted Average Exercise Price (in Dollars per share)		$ 11.14	$ 9.43
Expired Number of Shares	(22,000)	(164,000)	(175,000)
Expired Weighted Average Exercise Price (in Dollars per share)	$ 17.62	$ 13.94	$ 12.47
Granted Number of Shares	297,014	451,302	710,530
Granted Weighted Average Exercise Price (in Dollars per share)	$ 4.43	$ 3.38	$ 3.40
Outstanding Number of Shares	2,089,970	1,814,956	2,093,654	1,640,624
Outstanding Weighted Average Exercise Price (in Dollars per share)	$ 5.99	$ 6.39	$ 8.91	$ 11.71
Outstanding Weighted Average Remaining Contractual Term	6 years 146 days	7 years 36 days	7 years 219 days	6 years 292 days
Outstanding Aggregate Intrinsic Value (in Dollars)	$ 1,451
Exercisable at December 31, 2012	1,090,742
Exercisable at December 31, 2012 (in Dollars per share)	$ 7.94
Exercisable at December 31, 2012	6 years 255 days
Exercisable at December 31, 2012 (in Dollars)	$ 574