Income taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Income Tax [Line Items]
Income tax expense	$ (3,576,000)	$ 1,395,000
Operating loss carryforwards	16,000,000
Operating loss carryforwards, limitations on use	Approximately $10,600,000 of the Company’s $16,000,000 of NOLs are subject to annual limitations of $1,300,000
State and local income tax expense (benefit), continuing operations		5,395,000
Deferred tax assets		4,000,000
Income (loss) before income taxes	$ (9,418,000)	$ 14,196,000