v3.19.3.a.u2

Debt (Details)		3 Months Ended								12 Months Ended
	May 22, 2019 USD ($)	Dec. 31, 2019 USD ($) agreement	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) agreement	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Feb. 25, 2020 USD ($)
Debt Instrument [Line Items]
Long-term debt, current maturities		$ 600,000				$ 0				$ 600,000	$ 0
Incremental issuance costs		7,238,000				0				7,238,000	0
Required unrestricted cash as of last day of each fiscal quarter		25,000,000.0								25,000,000.0
Minimum Graduate LQAR		432,900,000								432,900,000
Minimum Alternative Credential LTMR		218,800,000								218,800,000
Minimum Graduate LQAR, minimum requirement		397,800,000								397,800,000
Minimum Alternative Credential LTMR, minimum requirement		185,000,000.0								185,000,000
Interest expense		5,289,000	$ 5,651,000	$ 2,424,000	$ 55,000	27,000	$ 27,000	$ 27,000	$ 27,000	13,419,000	108,000	$ 87,000
Maximum borrowing capacity on line of credit				$ 25,000,000.0
Long-term line of credit		$ 0				0				$ 0	0
Number of outstanding conditional loan agreements | agreement		2								2
Deferred government grant obligations		$ 3,500,000				3,500,000				$ 3,500,000	3,500,000
Letter of Credit | Credit Agreement
Debt Instrument [Line Items]
Debt instrument, face amount	$ 250,000,000
Interest rate during period (as a percent)										8.91%
Interest expense										$ 13,200,000
Interest payable		100,000								100,000
Letter of Credit | Credit Agreement | Maximum
Debt Instrument [Line Items]
Long-term debt, additional amount available	$ 50,000,000
Letter of Credit | Credit Agreement | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	5.75%
Letter of Credit | Credit Agreement | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	2.00%
Letter of Credit | Credit Agreement | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	6.75%
Letter of Credit | Credit Agreement | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.00%
Deferred Government Grant Obligations
Debt Instrument [Line Items]
Interest payable		300,000				$ 200,000				300,000	$ 200,000
Prince Georges County Maryland
Debt Instrument [Line Items]
Deferred government grant obligations		$ 1,500,000								$ 1,500,000
Interest rate per annum (as a percent)		3.00%								3.00%
Principal no longer subject to forgiveness		$ 600,000								$ 600,000
Accrued interest no longer subject to forgiveness		100,000								100,000
Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity on line of credit		$ 18,400,000								$ 18,400,000
Subsequent Event | Letter of Credit | Credit Agreement
Debt Instrument [Line Items]
Incremental issuance costs													$ 2,500,000
Prior To First Anniversary of First Amendment Effective Date | Letter of Credit | Credit Agreement
Debt Instrument [Line Items]
Prepayment premium	2.00%
Prepayment penalty	1.00%
On Or After First Anniversary of First Amendment Effective Date | Letter of Credit | Credit Agreement
Debt Instrument [Line Items]
Prepayment premium	1.00%

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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The average effective interest rate during the reporting period.

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Contractual interest rate for funds borrowed, under the debt agreement.

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