Acquisitions and Dispositions - Components of Total Consideration Paid, Payable or Issued Upon Closing of Merger (Details) - USD ($) $ in Thousands			12 Months Ended
	Jan. 31, 2017	Jan. 17, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Repayment of Media General debt, including premium and accrued interest			$ 1,922,329	$ 80,140	$ 166,290
Media General [Member]
Business Acquisition [Line Items]
Cash Consideration		$ 1,376,108
Nexstar Common Stock issued (15,670,094 shares)		995,835
Reissued Nexstar Common Stock from treasury (560,316 shares)		35,608
Stock option replacement awards (228,438 options)		10,702
Contingent consideration liability (CVR)		271,008
Total Consideration		4,347,396
Media General [Member] | Term Loans [Member]
Business Acquisition [Line Items]
Repayment of Media General debt, including premium and accrued interest	$ 668,800	$ 1,658,135