Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets [Abstract]
Accounts receivable, reserves	$ 4,523	$ 5,128
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	120,000	120,000
Common stock, shares issued	103,341	102,237
Deferred stock units, outstanding	231	240
Treasury stock, shares	15,367	12,242