Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 5,139	$ 5,242
Accumulated amortization on intangible assets	$ 9,568	$ 8,533
Preferred stock, par value (in dollars per shares)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	60,000,000	60,000,000
Common stock, shares issued (in shares)	30,512,843	30,219,278
Common stock, shares outstanding (in shares)	30,512,843	30,219,278
Treasury stock, shares (in shares)	1,334,251	1,175,795