Commitments and Contingencies (Details 2) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
HollyFrontier Corporation
Long-term commitments
Expenses related to agreement	$ 1,500,000	$ 500,000
Material \| Linde, Inc. \| CRNF
Long-term commitments
Committed contractual payments	300,000
Expenses related to agreement	$ 1,000,000	$ 1,200,000

The minimum amount the entity agreed to spend under the long-term purchase commitment.

No definition available.

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration