Business Segments and Geographic Areas - Summary of Company's Revenues from External Customers and Long-Lived Assets, by Geographical Areas (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues	$ 144,853	$ 158,093	$ 167,136	$ 164,016	$ 186,751	$ 214,733	$ 198,547	$ 204,197	$ 634,098	$ 804,228	$ 836,270
Total Long-Lived Assets	903,977				883,529				903,977	883,529
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues									579,300	722,339	747,063
Total Long-Lived Assets	751,290				773,939				751,290	773,939
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues									54,798	81,889	$ 89,207
Total Long-Lived Assets	$ 152,687				$ 109,590				$ 152,687	$ 109,590