Summary of Stock Award Activity and Related Information (Parenthetical) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Shares Available for future Grants, Balances	1,519,800	[1]	2,511,625
Replacement stock options were unused	228,438
Stock Options [Member]
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Replacement stock options were unused	228,438		0	200,000
Nexstar [Member] | Stock Options [Member]
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Replacement stock options were unused	7,987
Nexstar [Member] | Stock Options [Member] | Class A Common Stock [Member]
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Common stock market price at the end of reporting period (in dollars per share)	$ 78.20
Nexstar [Member] | 2015 Plan [Member] | Stock Options [Member]
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Shares Available for future Grants, Balances	1,454,938
Nexstar [Member] | 2012 Plan [Member] | Stock Options [Member]
Non-vested Shares, Weighted-Average Grant-Date Fair Value [Roll Forward]
Shares Available for future Grants, Balances	56,875

[1] Includes 1,454,938 shares and 56,875 shares available for future grants under the 2015 Plan and the 2012 Plan, respectively. Additionally, 7,987 shares associated with the merger replacement stock options were unused.