Leases - Additional information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Leased Assets [Line Items]
Operating lease right-of-use assets (Note 16)	$ 193,897	$ 194,000	$ 0
Operating lease, liability	119,139	119,000
Other	(39,257)		(129,312)
Other current liabilities	$ (114,361)		$ (184,229)
Accounting Standards Update 2016-02
Operating Leased Assets [Line Items]
Other		85,000
Other current liabilities		$ 10,000