Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Allowance for doubtful accounts	$ 489	$ 235
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 25	$ 25
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0667	$ 0.0667
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	31,757,861	31,528,449
Common stock, shares outstanding (in shares)	31,757,861	31,527,360
Treasury stock (in shares)	0	1,089