Quarterly report pursuant to Section 13 or 15(d)

Variable Interest Entities (Details)

v2.4.1.9
Variable Interest Entities (Details) (Black Bison and Intermediate Holdings [Member], USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Black Bison and Intermediate Holdings [Member]
     
Variable Interest Entity [Line Items]      
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount $ 15.7us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount
/ us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis
= corr_BlackBisonandIntermediateHoldingsMember
$ 15.9us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount
/ us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis
= corr_BlackBisonandIntermediateHoldingsMember
$ 15.7us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount
/ us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis
= corr_BlackBisonandIntermediateHoldingsMember