Inventory Financing Agreements (Textual) (Detail) barrel / d in Thousands		3 Months Ended
	Jun. 01, 2015 USD ($) barrel / d extension	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Feb. 29, 2016 USD ($) installment	Sep. 01, 2015 USD ($) payment
Supply Commitment [Line Items]
Supply and exchange agreement expenses		$ 8,942,000	$ 4,613,000
Supply and Offtake Agreements
Supply Commitment [Line Items]
Agreement term	3 years
Number of commitment extensions | extension	2
Commitment period	1 year
Barrels of crude per day provided by J. Aron | barrel / d	94
Handling fees		3,100,000	1,900,000
Supply and exchange agreement expenses		800,000	$ 600,000
Amount of deferred payment arrangement	$ 125,000,000
Percentage of receivables and inventory for deferred payment arrangement	85.00%
Deferral arrangement fee	$ 1,300,000
Description of Variable Rate Basis	90
Capacity of deferred payment arrangement		55,400,000		$ 59,400,000
Outstanding amount of deferred payment arrangement		41,400,000		43,300,000
Fee agreement receivable					$ 14,600,000	$ 18,000,000
Number of fee agreement payments					18	14
Fee agreement receivable		$ 12,200,000		$ 14,600,000
London Interbank Offered Rate (LIBOR) | Supply and Offtake Agreements
Supply Commitment [Line Items]
Margin on LIBOR rate	3.75%
Deferred payment availability fee	0.75%