CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common stock	Additional paid-in capital	Retained earnings	Treasury stock, at cost	Non-controlling interests
Balance at Dec. 31, 2013	$ 157,741	$ 25,413	$ 89,273	$ 239,561	$ (197,548)	$ 1,042
Balance (in shares) at Dec. 31, 2013		25,413
Increase (Decrease) in Equity
Net income	40,146			39,631		515
Distributions to non-controlling interest holders	(653)					(653)
Share-based compensation expense	658		658
Exercise of stock options	401			(1,732)	2,133
Repurchase of shares	(35,766)				(35,766)
Balance at Mar. 31, 2014	162,527	25,413	89,931	277,460	(231,181)	904
Balance (in shares) at Mar. 31, 2014		25,413
Balance at Dec. 31, 2014	41,443	25,413	91,509	367,967	(444,495)	1,049
Balance (in shares) at Dec. 31, 2014		25,413
Increase (Decrease) in Equity
Net income	4,408			3,698		710
Distributions to non-controlling interest holders	(657)					(657)
Share-based compensation expense	443		443
Exercise of stock options	203			(1,701)	1,904
Repurchase of shares	(3,959)				(3,959)
Balance at Mar. 31, 2015	$ 41,881	$ 25,413	$ 91,952	$ 369,964	$ (446,550)	$ 1,102
Balance (in shares) at Mar. 31, 2015		25,413