Stockholders' equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders Equity Note [Abstract]

Summary of changes in common shares outstanding

The following is a summary of the changes in our common shares outstanding:

	Common Stock
	Class A			Class B			Class C			Class E			Class F			Class G			Total
Shares issued at January 1, 2015 - Predecessor		364,896			344,859			209,882			504,276			1			2			1,423,916
Restricted stock issuance		1,209			—			—			—			—			—			1,209
Restricted stock repurchased		(5,725	)		—			—			—			—			—			(5,725	)
Restricted stock forfeited		(15,091	)		—			—			—			—			—			(15,091	)
Shares issued at December 31, 2015 - Predecessor		345,289			344,859			209,882			504,276			1			2			1,404,309
Restricted stock repurchased		(2,597	)		—			—			—			—			—			(2,597	)
Restricted stock forfeited		(9,006	)		—			—			—			—			—			(9,006	)
Shares issued at December 31, 2016 - Predecessor		333,686			344,859			209,882			504,276			1			2			1,392,706
Restricted stock forfeited		(1,454	)		—			—			—			—			—			(1,454	)
Restricted stock cancelled		(8,964	)		—			—			—			—			—			(8,964	)
Shares issued at March 21, 2017 - Predecessor		323,268			344,859			209,882			504,276			1			2			1,382,288
Cancellation of Predecessor equity		(323,268	)		(344,859	)		(209,882	)		(504,276	)		(1	)		(2	)		(1,382,288	)
Shares issued at March 21, 2017 - Predecessor		—			—			—			—			—			—			—
Issuance of Successor common stock - rights offering		4,197,210			—			—			—			—			—			4,197,210
Issuance of Successor common stock - backstop premium		367,030			—			—			—			—			—			367,030
Issuance of Successor common stock - settlement of claims		32,546,390			7,871,512			—			—			—			—			40,417,902
Shares issued at March 21, 2017 - Successor		37,110,630			7,871,512			—			—			—			—			44,982,142
Stock-based compensation		1,853,236			—			—			—			—			—			1,853,236
Restricted stock cancelled		(7,616	)		—			—			—			—			—			(7,616	)
Shares issued at December 31, 2017 - Successor		38,956,250			7,871,512			—			—			—			—			46,827,762