Acquisition of Florida Chemical Company, Inc. - Pro Forma (Details) (Florida Chemical Company, Inc [Member], USD $)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Florida Chemical Company, Inc [Member]
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	$ 10,000,000
Revenue	395,407,000	391,786,000
Net income	$ 38,271,000	$ 53,902,000
Earnings per common share:
Basic	$ 0.73	$ 1.05
Diluted	$ 0.70	$ 0.98

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

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