CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Property, building and equipment, accumulated depreciation	$ 46,195	$ 43,565
Intangible assets, accumulated amortization	$ 13,482	$ 13,041
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	40,000,000	40,000,000
Common stock, issued	22,811,147	22,640,046
Treasury stock at cost, shares	4,947,276	4,890,504
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	5,000,000	5,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0