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Commitments and Contingencies - Summary of Asset Retirement Obligations (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
May 31, 2017
May 31, 2016
May 31, 2017
May 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]        
Balance at the beginning of the period $ 14,129 $ 10,658 $ 13,448 $ 9,992
ARO assumed in acquisition 0 981 493 1,528
Accretion expense 186 127 357 246
Revisions to ARO during the period 4 (224) 21 (224)
Balance at the end of the period $ 14,319 $ 11,542 $ 14,319 $ 11,542