Investments in Unconsolidated Affiliates - Combined Financial Information of Unconsolidated Affiliated Companies (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Assets:
Current assets	$ 58,048		$ 58,048
Noncurrent assets	118,228		118,228
Total assets	176,276		176,276
Liabilities:
Current liabilities	38,067		38,067
Noncurrent liabilities	49,731		49,731
Total liabilities	87,798		87,798
Results of operations:
Revenue	52,195	$ 39,912	89,763	$ 63,525
Operating income	6,367	1,709	3,795	(6,629)
Income from continuing operations	3,734	83	2,092	6,393
Net income	$ 3,734	$ 83	$ 2,092	$ 6,393