Subsequent Events - Additional Information (Detail)			3 Months Ended	6 Months Ended
	Aug. 13, 2018 shares	Jul. 19, 2018	Jun. 30, 2018 $ / shares shares	Jun. 30, 2018 $ / shares shares	Aug. 01, 2018 shares	Dec. 31, 2017 shares
Subsequent Event [Line Items]
Common shares, shares outstanding			92,532,749	92,532,749		93,045,152
Basic earnings (loss) per share | $ / shares			$ (27.26)	$ (45.82)
Diluted earnings (loss) per share | $ / shares			$ (27.26)	$ (45.82)
Weighted average shares outstanding, basic			1,839,826	1,838,666
Weighted average shares outstanding, diluted			1,839,826	1,838,666
Scenario, Forecast
Subsequent Event [Line Items]
Reverse stock split, conversion ratio	0.02
Common shares, shares outstanding	1,850,655
Subsequent Event
Subsequent Event [Line Items]
Common shares, shares outstanding					92,532,749
Reverse stock split description		When the reverse stock split becomes effective, every fifty common shares issued and outstanding will be automatically combined into one issued and outstanding common share. Upon the effective date of the reverse stock split, the 92,532,749 common shares outstanding on August 1, 2018 will be reduced to approximately 1,850,655 common shares, without giving effect to any fractional shares that result from the reverse stock split and assuming no additional common shares are issued between the date of this report and the effective date.