Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Summary of quarterly financial data

Summarized quarterly financial data are as follows:

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Full Year
	(in millions, except per unit amounts)
2017
Net sales	$	119.0	$	96.1	$	84.6	$	97.5	$	397.2
Gross margin	46.6		43.5		27.2		39.4		156.7
Net earnings (1)	42.2		39.5		22.8		49.4		153.9
Net earnings per Common Unit (1) (2)	2.10		1.48		0.92		1.44		5.93
2016
Net sales	$	108.0	$	126.7	$	90.2	$	93.4	$	418.3
Gross margin	43.1		102.7		32.8		48.2		226.8
Net earnings	37.7		98.7		28.8		44.1		209.3
Net earnings per Common Unit (2)	1.44		3.22		1.04		1.85		7.56

⁽¹⁾  The fourth quarter of 2017 includes a gain of $14.3 million for the sale of our 50% joint venture interest in Oklahoma CO2 Partnership (OKCO2). See Note 14—Sale of Equity Method Investment.

⁽²⁾  The sum of the four quarters is not necessarily the same as the total for the year.