Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other assets noncurrent:
Other intangibles, accumulated amortization	$ 17,667	$ 13,460
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	40,394,000	39,018,000
Treasury stock at cost, shares	1,487,000	1,484,000
Acquired Technology [Member]
Other assets noncurrent:
Acquired technology, accumulated amortization	$ 36,091	$ 24,778