Income Taxes - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 01, 2015
Income Taxes [Line Items]
Net operating loss carryovers		$ 1,600,000
Deferred tax asset, increase (decrease)		59,000
Income (loss) before income taxes, foreign		1,400	$ 900	$ 1,400
Alternative minimum tax credit carryovers		$ 785
Minimum
Income Taxes [Line Items]
Net operating loss carryforwards expiration year		2027
Maximum
Income Taxes [Line Items]
Net operating loss carryforwards expiration year		2035
Mid Pac Petroleum, LLC
Income Taxes [Line Items]
Deferred tax liability			$ 16,800		$ 16,759
5% Convertible Senior Notes due 2021
Income Taxes [Line Items]
Deferred tax asset, increase (decrease)	$ 8,600