Share-based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock compensation	$ 4,854	$ 7,688	$ 8,004	$ 3,931
Continuing operations
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock compensation	4,748	7,261	7,735	3,184
Continuing operations | Stock options, net of estimated forfeitures
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock compensation	1,340	1,982	2,163	(5,265)
Continuing operations | Restricted stock awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock compensation	3,408	5,279	5,572	8,449
Discontinued operations
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock compensation	$ 106	$ 427	$ 269	$ 747