Discontinued Operations (Summarized Results from Discontinued Operations) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Revenues	$ 9	$ 4,270
Cost of sales	(6)	(4,964)
Other operating expenses	(54)	(1,323)
Loss from discontinued operations before income taxes	(51)	(2,017)
Loss on sale of assets before income taxes	0	(10,977)
Income tax benefit	469	4,778
Income (loss) from discontinued operations, net of taxes	$ 418	$ (8,216)