Equity - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Equity [Line Items]
Proceeds from issuance of common stock	$ 151	$ 1,326
Class A Common Stock
Equity [Line Items]
Issuance of common stock options exercises	27,000
Proceeds from issuance of common stock	$ 200
Class A Common Stock | Long-Term Incentive Plan 2009
Equity [Line Items]
Issuance of shares for compensation	10,000