CONDENSED CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 9,736	$ 9,445
Preferred stock, par value per share (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized	250,000	250,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	61,074,913	60,870,749
Common stock, shares outstanding	61,074,913	60,870,749
Treasury stock, shares	6,374,882	6,374,882