CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowances (in dollars)	$ 5,437	$ 4,825
Other accounts receivable, allowances (in dollars)	$ 849	$ 1,029
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	70,000,000	70,000,000
Common stock, issued shares	28,174,424	27,938,319
Treasury stock, at cost, shares	2,565,399	2,080,187