Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other assets noncurrent:
Trademarks and other intangibles, accumulated amortization	$ 10,733	$ 7,997
Shareholders' equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	34,230,000	29,766,000
Treasury stock at cost, shares	1,356,000	1,265,000
Series A Junior Participating Preferred Stock [Member]
Shareholders' equity:
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Convertible Preferred Stock [Member]
Shareholders' equity:
Preferred stock, shares authorized	460,000	460,000
Preferred stock, shares issued	0	0
Patents [Member]
Other assets noncurrent:
Accumulated amortization	$ 2,702	$ 2,664