Financial Instruments and Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2014	Dec. 31, 2008	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt principal amount		$ 180,000
Debt interest rate		4.80%
Retained interest promissory note receivable	$ 15,100
Notes, maturity period			15 years
Senior Notes Held By Special Purpose Entity	176,147			$ 176,094
Unamortized discount and debt issuance costs	688			720
Carrying Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained interest, fair value	10,316			10,246
Senior Notes Held By Special Purpose Entity	$ 176,147			$ 176,094
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note maturity year			2022
Retained interest, effective interest rate	3.70%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note maturity year			2024
Retained interest, effective interest rate	11.40%
AgReserves Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note received in sale of real estate		$ 200,000
Maturity of installment note		15 years
Special Purpose Entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. Treasuries Held By Special Purpose Entities	$ 8,100
Cash Held By Special Purpose Entities	300
Senior Notes Held By Special Purpose Entity	176,100
Unamortized discount and debt issuance costs	3,900
Buyer Special Purpose Entity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time Deposits Held By Special Purpose Entities	$ 200,000
Notes Receivable | Subsidiaries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issue price of Senior Secured Notes		98.50%
Notes Receivable | Special Purpose Entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt interest rate	4.006%