Leases - Additional Information (Details) ft² in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) ft²	Apr. 25, 2019 USD ($) ft²	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 31, 2018 USD ($) ft²
Lessee, Lease, Description [Line Items]
Operating and finance lease, maximum term of extension option	5 years
Operating and finance lease, term of termination option	1 year
Area of space leased (in square feet) | ft²	1,000
Restructuring reserve			$ 85,800	$ 85,800
Total base rent obligation	$ 596,012
Nashville
Lessee, Lease, Description [Line Items]
Area of space leased (in square feet) | ft²					205
Operating lease, lease not yet commenced, term of contract					15 years
Total base rent obligation					$ 126,000
Subsequent Event | New York City
Lessee, Lease, Description [Line Items]
Area of space leased (in square feet) | ft²		190
Operating lease, lease not yet commenced, term of contract		20 years
Total base rent obligation		$ 448,000
Minimum
Lessee, Lease, Description [Line Items]
Operating and finance lease, remaining contract term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating and finance lease, remaining contract term	11 years