Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental non-cash investing and financing activities:
Value of common stock issued in acquisitions	$ 3,268	$ 1,014	$ 2,043
Final Florida Chemical acquisition adjustment	0	0	1,162
Value of common stock issued in payment of accrued liability	0	0	600
Exercise of stock options by common stock surrender	50	1,332	1,198
Supplemental cash payment information:
Interest paid	2,024	1,398	1,285
Income taxes paid, net of refunds	$ 333	$ 1,547	$ 22,389