Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Depreciation expense for continuing operations	$ 21,900	$ 24,800	$ 52,600
Depreciation expense for discontinued operations	0	0	2,073
Asset impairment charges	$ 1,200	$ 41,700	$ 25,000