Impairment of Long Lived Assets - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010	Mar. 31, 2012 Land and building [Member]	Dec. 31, 2012 Land and building [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets	$ 1,675,000	$ 12,576,000	$ 1,700,000	$ 0
Net book value of assets	$ 1,400,000			$ 2,800,000
Method for determining fair value	Probability-weighted discounted cash flow model of the future estimated net sublease income