Discontinued Operations and Assets Held for Sale - Summary of Major Classes of Assets and Liabilities Reclassified to Held for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets of Discontinued Operations
Subtotal: assets of Discontinued Operations	$ 1,122,082	$ 1,917,435
Liabilities of Discontinued Operations
Total liabilities held for sale	186,260	702,256
Discontinued operations
Liabilities of Discontinued Operations
Deferred revenue and student deposits	79,908	87,793
Operating leases, including current portion	19,645	151,413
Long-term debt, seller notes and finance leases, including current portion	0	171,451
Other liabilities	86,707	291,599
Discontinued Operations, Held-for-sale
Assets of Discontinued Operations
Cash and cash equivalents	105,217	270,164
Receivables, net	42,452	113,386
Property and equipment, net	43,082	259,471
Goodwill and Tradenames	822,440	1,202,496
Operating lease right-of-use assets, net	13,651	136,806
Other assets	95,240	183,742
Valuation allowance on held-for-sale disposal groups	$ 0	$ (248,630)