Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental non-cash investing and financing activities:
Value of common stock issued in acquisitions	$ 1,014	$ 2,043	$ 52,711
Final Florida Chemical acquisition adjustment	0	1,162	0
Value of common stock issued in payment of accrued liability	0	600	0
Equipment acquired through capital leases	0	0	754
Exercise of stock options by common stock surrender	1,332	1,198	3,907
Supplemental cash payment information:
Interest paid	1,398	1,285	1,859
Income taxes paid, net of refunds	$ 1,547	$ 22,389	$ 17,783