Significant Accounting Policies - Tuition Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Tuition receivable	$ 79,429		$ 82,454
Allowance for credit losses	(38,094)		(30,931)	$ (29,387)	$ (28,457)
Tuition receivable, net	$ 41,335	$ 51,523	$ 51,523

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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