Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets [Abstract]
Accounts receivable, reserves	$ 5,128	$ 4,306
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	102,237,000	101,947,000
Deferred stock units, outstanding	240,000	235,000
Treasury stock, shares	12,242,000	54,574,000