Share-Based and Long-Term Incentive Compensation - Share Based Compensation Expense (Income) Included in Operating Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based and Long Term Incentive Compensation	$ 1,448	$ 412	$ 2,343	$ 1,956
General and administrative expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based and Long Term Incentive Compensation	823	338	1,486	1,844
Other Operating Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based and Long Term Incentive Compensation	$ 625	$ 74	$ 857	$ 112