CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Accounts receivable, less allowance for doubtful accounts	$ 20,070	$ 20,608
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	74,435,628	74,435,628
Treasury stock, shares	34,971,702	34,714,083