Income Taxes - Summary of Reconciliation of the Income Tax (Benefit) Expense at the Statutory Income Tax Rate and the Effective Tax Rate for Income from Continuing Operations before Income Taxes (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax at the US statutory federal rate	35.00%	35.00%	35.00%