Investments in Unconsolidated Affiliates - Combined Financial Information of Unconsolidated Affiliated Companies (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Assets:
Current assets	$ 67,711		$ 67,711
Noncurrent assets	118,514		118,514
Total assets	186,225		186,225
Liabilities:
Current liabilities	39,416		39,416
Noncurrent liabilities	84,051		84,051
Total liabilities	123,467		123,467
Results of operations:
Revenue	58,300	$ 41,252	148,063	$ 104,777
Operating income (loss)	11,552	(3,505)	15,356	(10,134)
Income from continuing operations	6,710	2,694	8,802	9,087
Net income	$ 6,710	$ 2,694	$ 8,802	$ 9,087