Annual report pursuant to Section 13 and 15(d)

Supplemental Oil and Gas Disclosures - Capitalized Costs Not Subject to Amortization (Details)

v3.3.1.900
Supplemental Oil and Gas Disclosures - Capitalized Costs Not Subject to Amortization (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Costs excluded by year incurred:        
Acquisition costs, Total $ 13.9      
Capitalized interest not subject to amortization, Total 4.7      
Total costs not subject to amortization, Total 18.6      
Acquisition costs   $ 0.5 $ 4.9 $ 8.5
Capitalized interest not subject to amortization 1.5 1.2 0.9 1.1
Total costs not subject to amortization $ 1.5 $ 1.7 $ 5.8 $ 9.6