- Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019	Jan. 01, 2018
Disaggregation of Revenue [Line Items]
Accounts and notes receivable	$ 432,910,000	$ 373,855,000
Deferred revenue and student deposits, current	216,816,000	193,226,000
Capitalized contract cost	23,900,000	11,500,000
Capitalized contract cost, accumulated amortization	12,300	4,400,000
Amortization of capitalized costs	$ 10,200,000	$ 4,400,000
Minimum
Disaggregation of Revenue [Line Items]
Contract cost, amortization period	2 years
Maximum
Disaggregation of Revenue [Line Items]
Contract cost, amortization period	4 years
Commission and Bonuses
Disaggregation of Revenue [Line Items]
Remaining performance obligations recognition period	one year or less
Incremental Costs Of Obtaining A Contract With Customer
Disaggregation of Revenue [Line Items]
Remaining performance obligations recognition period	one year or less
Incremental Cost Of Obtaining A Contract With Students
Disaggregation of Revenue [Line Items]
Remaining performance obligations recognition period	one year or less
(Accumulated deficit) retained earnings
Disaggregation of Revenue [Line Items]
Adoption of accounting standards			$ 28,944,000
(Accumulated deficit) retained earnings | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Adoption of accounting standards				$ 1,400,000