Earnings per Share - Schedule of Computation of Basic and Diluted EPS (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Net Income	$ 21,767	$ 14,185
Noncontrolling interests	171	(225)
Net Income Attributable to Common Stockholders	$ 21,938	$ 13,960
Shares:
Basic: Weighted-average number of shares outstanding	9,116	7,820
Plus: Incremental shares from assumed conversion of dilutive instruments	245	268
Diluted: Weighted-average number of shares outstanding	9,361	8,088
Earnings per share - basic	$ 2.41	$ 1.79
Earnings per share - diluted	$ 2.34	$ 1.73