Leases - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Operating lease, description	The Company has commitments under operating leases for office space and radio tower sites used in its operations. Our leases have initial lease terms that expire between 2019 and 2082, most of which include options to extend or renew the leases.
Lessee, operating lease, existence of option to extend	true
Operating lease, options to extend	Our leases have initial lease terms that expire between 2019 and 2082, most of which include options to extend or renew the leases.
Rental expenses	$ 900
Additional operating leases liability	$ 3,800
Additional operating leases expected to commence	10 years
Minimum
Lessee Lease Description [Line Items]
Initial lease term	2019
Rental expenses	$ 3
Maximum
Lessee Lease Description [Line Items]
Initial lease term	2082
Rental expenses	$ 500