Discontinued Operations and Assets Held for Sale - Summary of Major Classes of Assets and Liabilities Reclassified to Held for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Subtotal: assets of Discontinued Operations	$ 1,354,046	$ 1,549,340
Total liabilities held for sale	747,567	857,316
Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	209,148	197,898
Receivables, net	85,298	83,045
Property and equipment, net	637,639	830,408
Goodwill	131,958	159,042
Tradenames	126,292	156,746
Other assets	97,829	122,201
Subtotal: assets of Discontinued Operations	1,288,164	1,549,340
Deferred revenue and student deposits	211,086	223,163
Long-term debt, including current portion	275,024	319,473
Other liabilities	243,223	314,680
Total liabilities held for sale	729,333	857,316
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred revenue and student deposits	1,598	0
Long-term debt, including current portion	4,973	0
Other liabilities	11,663	0
Total liabilities held for sale	18,234	0
UniNorte Brazil | Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net	8,311	0
Property and equipment, net	15,254	0
Goodwill	21,665	0
Tradenames	7,664	0
Other assets	12,988	0
Subtotal: assets of Discontinued Operations	$ 65,882	$ 0