Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Sep. 13, 2016	Sep. 12, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, shares issued	15,018,870	14,992,018	14,992,018	14,992,018
Common stock, par value	$ 0.01	$ 0.01	$ 0.01	$ 12.73
Common stock, shares authorized	45,000,000	45,000,000
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Treasury stock (in shares)	0	0
Successor [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Accumulated other comprehensive losses attributable to pension and postretirement benefit obligations, net of tax	$ 0.0	$ 0.1
Predecessor [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Accumulated other comprehensive losses attributable to pension and postretirement benefit obligations, net of tax				$ 0.1	$ 0.4