Components Of Loss (Gain) On Disposal or Impairment Of Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Impairment Of Assets [Line Items]
Impairment of long-lived assets			$ 36,177
China assets impairment		$ 0
Goodwill and intangible assets impairment			9,497
Loss (gain) on disposal of assets	$ 19	(176)	(230)
Total	125,778	889	44,111
UNITED STATES
Impairment Of Assets [Line Items]
Impairment of long-lived assets	125,759	1,065	42,664
CHINA
Impairment Of Assets [Line Items]
China assets impairment			1,033
China CTA gain realization	$ 0	$ 0	$ (8,853)