Consolidated Statement of Changes in Equity - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock at Cost	Accumulated Other Comprehensive (Loss) Income	Non-controlling Interests
Beginning Balance (in shares) at Dec. 31, 2016		67,585,675			25,747,541
Beginning Balance at Dec. 31, 2016	$ 542,557	$ 676	$ 199,414	$ 1,512,993	$ (1,167,437)	$ (3,089)
Net income (loss)	112,313			112,336			$ (23)
Dividends ($0.28 per share)	(11,739)			(11,739)
Issuance of stock related to stock-based compensation plans (in shares)		129,615			1,952
Issuance of stock related to stock-based compensation plans	2,160	$ 1	2,322		$ (163)
Stock-based compensation	3,660		3,660
Other comprehensive income	1,381					1,381
Acquired business and noncontrolling interests	3,641						3,641
Ending Balance (in shares) at Sep. 30, 2017		67,715,290			25,749,493
Ending Balance at Sep. 30, 2017	$ 653,973	$ 677	$ 205,396	$ 1,613,590	$ (1,167,600)	$ (1,708)	$ 3,618