Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Receivables, allowance	$ 14,431	$ 15,182
Intangible assets, accumulated amortization	$ 89,713	$ 82,406
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued	0	0
Common stock, par value (in usd per share)	$ 0.30	$ 0.30
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	30,293,191	30,184,330