Earnings per Share - Schedule of Computation of Basic and Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net (Loss) Income	$ (3,703)	$ 36,995	$ 25,034	$ 78,554
Noncontrolling interests	3,054	345	3,436	267
Net (Loss) Income Attributable to Common Stockholders	$ (649)	$ 37,340	$ 28,470	$ 78,821
Shares:
Basic: Weighted-average number of shares outstanding (in shares)	8,775	9,096	8,876	9,115
Plus: Incremental shares from assumed conversion of dilutive instruments (in shares)	0	183	163	207
Diluted: Weighted-average number of shares outstanding (in shares)	8,775	9,279	9,039	9,322
(Loss) Earnings per share—Basic (in $ per share)	$ (0.07)	$ 4.10	$ 3.21	$ 8.65
(Loss) Earnings per Share—Diluted (in $ per share)	$ (0.07)	$ 4.02	$ 3.15	$ 8.46