Earnings Per Share Attributable to Common Stockholders - Additional Information (Detail) - Common stock - Stock Repurchase Program $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Class Of Stock [Line Items]
Common stock repurchased and retired, Shares | shares	724,473
Common stock repurchased and retired, average price paid per share | $ / shares	$ 20.37
Common stock repurchased and retired | $	$ 14,774