Related Party Transactions - Hydrogen Purchase and Sale Agreement (Details) $ in Thousands		3 Months Ended
	Jan. 01, 2017 Mcf	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Related Party Transaction [Line Items]
Accounts payable		$ 25,753	$ 28,815
CRNF | Hydrogen | CRRM | Hydrogen Purchase and Sale Agreement
Related Party Transaction [Line Items]
Monthly production volume of product to be delivered | Mcf	90,000
Optional excess volume that can be purchased | Mcf	60,000
Term of agreement	20 years
Additional renewal term	5 years
Minimum notice period for termination of agreement	180 days
Cost of purchases		1,200
Accounts payable		$ 500