Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Supplemental non-cash investing and financing activities:
Value of common stock issued in acquisitions	$ 2,043	$ 52,711
Final Florida Chemical acquisition adjustment	1,162	0
Value of common stock issued in payment of accrued liability	600	0
Equipment acquired through capital leases	0	866
Exercise of stock options by common stock surrender	1,183	2,979
Supplemental cash payment information:
Interest paid	1,038	1,410
Income taxes paid	$ 18,393	$ 13,343