Schedule I - Parent Company Financial Information - Statements of Operations and Retained Earnings (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Other operating expenses	$ 363,986	$ 381,954	$ 347,276
Affiliates
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Other operating expenses	$ 276	$ 276	$ 276