Intangibles - Amortizable Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Indefinite-lived licenses	$ 100,138	$ 90,209
Noncompetition agreements	84,022	103,510
Customer relationships and other	52,566	23,887
Intangible assets, gross (excluding goodwill)	236,726	217,606
Less accumulated amortization	(70,141)	(81,922)
Total intangible assets	$ 166,585	$ 135,684