Loss Per Share - Average Market Price of Common Stock and the Incremental Shares that were Dilutive or Potentially Dilutive (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Average market price of Real Industry common stock	$ 2.13	$ 7.27	$ 3.26	$ 7.43
Potentially dilutive common stock equivalents:
Total potentially dilutive common stock equivalents	3,113,459	3,122,217	3,113,459	3,122,217
Restricted Common Stock Awards
Potentially dilutive common stock equivalents:
Total potentially dilutive common stock equivalents	700,191	571,676	700,191	571,676
Outstanding Common Stock Options
Potentially dilutive common stock equivalents:
Total potentially dilutive common stock equivalents	445,100	748,150	445,100	748,150
Unvested Restricted Stock Units
Potentially dilutive common stock equivalents:
Total potentially dilutive common stock equivalents	519,835	354,058	519,835	354,058
Warrants
Potentially dilutive common stock equivalents:
Total potentially dilutive common stock equivalents	1,448,333	1,448,333	1,448,333	1,448,333