CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
ASSETS
Accumulated depreciation	$ 245,091	$ 220,028
STOCKHOLDERS' EQUITY:
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	49,072,710	48,671,492
Common stock, shares outstanding	49,072,710	48,671,492