Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful receivables	$ 5,367	$ 3,932
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	152,676	151,514
Other intangible assets, accumulated amortization	$ 15,345	$ 15,186
Common stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.02	$ 0.02
Common stock, shares issued	26,629,750	26,574,031
Treasury stock, shares	10,571,419	10,557,342