CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
ASSETS
Property and equipment, accumulated depreciation	$ 154,405	$ 146,553
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	47,575,692	47,556,056
Common stock, shares outstanding	47,575,692	47,556,056