Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Future minimum lease payments	$ 1,160,832
Future minimum sublease income	202
Net rent expense	$ 169,172	$ 170,099	$ 171,215
Equipment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Term of operating lease contract	60 months
Disposal Group, Held-for-sale, Not Discontinued Operations | UniNorte Brazil
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Future minimum lease payments	$ 13,000