CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Treasury stock, at cost	Non-controlling interests
Balance at Dec. 31, 2012	$ 159,829	$ 25,413	$ 86,873	$ 124,127	$ (77,954)	$ 1,370
Balance (in shares) at Dec. 31, 2012		25,413
Increase (Decrease) in Equity
Net income	133,793			129,973		3,820
Contributions from non-controlling interest holders	28					28
Distributions to non-controlling interest holders	(4,176)					(4,176)
Share-based compensation expense	2,400		2,400
Exercise of stock options	6,885			(14,539)	21,424
Value of common stock paid at acquisition	0
Repurchase of shares	(141,018)				(141,018)
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	137,087			134,484		2,603
Distributions to non-controlling interest holders	(2,596)					(2,596)
Share-based compensation expense	2,236		2,236
Exercise of stock options	2,688			(6,078)	8,766
Value of common stock paid at acquisition	0
Repurchase of shares	(255,713)				(255,713)
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	44,800			41,598		3,202
Distributions to non-controlling interest holders	(2,959)					(2,959)
Share-based compensation expense	4,812		4,812
Exercise of stock options	1,390			(8,292)	9,682
Issuance of restricted shares for acquisitions				(32,003)	53,736
Value of common stock paid at acquisition	21,733
Repurchase of shares	(58,949)				(58,949)
Balance at Dec. 31, 2015	$ 52,270	$ 25,413	$ 96,321	$ 369,270	$ (440,026)	$ 1,292
Balance (in shares) at Dec. 31, 2015		25,413