CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current Assets:
Trade accounts receivable, allowance for losses	$ 4,836	$ 3,871
Intangible assets, accumulated amortization	$ 16,314	$ 15,176
Shareholders' Equity:
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	53,954,874	53,954,874
Treasury stock, shares (in shares)	9,716,504	9,174,843