Income taxes - components of provision for income taxes from continuing operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (1,525)	$ 133,621	$ 2,344
State	1,432	5,213	5,230
Foreign	29,353	35,444	28,842
Deferred:
Federal	(5,124)	(258,247)	(25,141)
State	(5,114)	1,459	(1,837)
Foreign	4,174	212,158	(1,364)
Provision for income taxes from continuing operations	$ 23,196	$ 129,648	$ 8,074