Amortization of Deferred Grants (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
Amortization of Deferred Grant [Line Items]
Amortization of property grants	$ 235	$ 235	$ 705	$ 723
Amortization of employment grants	17	18	89	53
Amortization of deferred grants	$ 252	$ 253	$ 794	$ 776