Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Feb. 28, 2017
Other investment securities:
Capital transaction recorded in additional paid-in capital	$ (497,145)
Commercial paper | Maximum
Other investment securities:
Debt term of Maturity		365 days
Corporate securities | Maximum
Other investment securities:
Debt term of Maturity		18 months
NagraStar
Other investment securities:
Ownership interest (as a percent)			50.00%