Goodwill and Intangible Assets - Intangibles Excluding Goodwill (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Subject to amortization
Accumulated Amortization	$ (36,889)	$ (23,056)
Total
Gross Carrying Amount	351,400	351,400
Net	314,511	328,344
Trade names
Not subject to amortization
Net	185,400	185,400
Student relationships
Subject to amortization
Gross Carrying Amount	166,000	166,000
Accumulated Amortization	(36,889)	(23,056)
Net	$ 129,111	$ 142,944