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Acquisitions - 2019 Acquisition Summary of Fair Value of the Consideration (Details) - USD ($) $ in Thousands		12 Months Ended
	Jul. 02, 2018	Dec. 31, 2019	Dec. 31, 2018	Oct. 01, 2019	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 214,513	$ 149,524		$ 125,272
Thinkful, Inc
Business Acquisition [Line Items]
Cash				$ 51
Accounts receivable				547
Other acquired assets				1,710
Acquired intangible assets				16,360
Total identifiable assets acquired				18,668
Deferred revenue				(3,044)
Liabilities assumed				(1,605)
Net identifiable assets acquired				14,019
Goodwill				65,181
Total fair value of purchase consideration				$ 79,200
WriteLab, Inc. And StudyBlue, Inc.
Business Acquisition [Line Items]
Cash		234
Accounts receivable		482
Acquired intangible assets		11,550	$ 11,550
Total identifiable assets acquired		12,417
Liabilities assumed		(2,206)
Net identifiable assets acquired		10,211
Goodwill		24,673
Total fair value of purchase consideration		34,884
Weighted average amortization period			72 months
StudyBlue, Inc.
Business Acquisition [Line Items]
Cash	$ 152
Accounts receivable	288
Acquired intangible assets	7,100
Total identifiable assets acquired	7,691
Liabilities assumed	(1,309)
Net identifiable assets acquired	6,382
Goodwill	13,996
Total fair value of purchase consideration	$ 20,378
Weighted average amortization period	57 months
Trade name \| Thinkful, Inc
Business Acquisition [Line Items]
Acquired intangible assets		$ 4,430
Weighted average amortization period		48 months
Trade name \| WriteLab, Inc. And StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets			$ 140
Weighted average amortization period			12 months
Trade name \| StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets	$ 140
Weighted average amortization period	12 months
Domain names \| Thinkful, Inc
Business Acquisition [Line Items]
Acquired intangible assets		$ 330
Weighted average amortization period		48 months
Domain names \| WriteLab, Inc. And StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets			$ 180
Weighted average amortization period			12 months
Domain names \| StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets	$ 180
Weighted average amortization period	12 months
Content library \| Thinkful, Inc
Business Acquisition [Line Items]
Acquired intangible assets		$ 6,940
Weighted average amortization period		60 months
Content library \| WriteLab, Inc. And StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets			$ 5,220
Weighted average amortization period			60 months
Content library \| StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets	$ 5,220
Weighted average amortization period	60 months
Developed technology \| Thinkful, Inc
Business Acquisition [Line Items]
Acquired intangible assets		$ 4,660
Weighted average amortization period		36 months
Developed technology \| WriteLab, Inc. And StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets			$ 5,790
Weighted average amortization period			88 months
Developed technology \| StudyBlue, Inc.
Business Acquisition [Line Items]
Acquired intangible assets	$ 1,340
Weighted average amortization period	60 months
Acquired intangible assets \| Thinkful, Inc
Business Acquisition [Line Items]
Acquired intangible assets		$ 16,360
Weighted average amortization period		50 months