Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Statement of Financial Position [Abstract]
Trade receivables allowances	$ 19,545	$ 19,602	$ 18,122
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares outstanding	46,916,600	46,829,913	46,525,952