Condensed Consolidating Financial Information - Condensed Consolidated Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net broadcast revenue (including trade and barter)									$ 2,431,966	$ 1,103,190	$ 896,377
Net revenue	$ 653,664	$ 611,870	$ 626,115	$ 540,317	$ 309,879	$ 275,659	$ 261,994	$ 255,658	2,431,966	1,103,190	896,377
Operating expenses (income):
Direct operating expenses, excluding depreciation and amortization									993,405	381,997	302,257
Selling, general, and administrative expenses, excluding depreciation and amortization									591,986	263,606	232,480
Amortization of broadcast rights									105,403	57,145	59,836
Amortization of intangible assets									159,500	46,572	48,475
Depreciation									100,658	51,300	47,222
Goodwill and intangible assets impairment									19,985	15,262
Gain on disposal of stations, net									(57,716)
Total operating expenses									1,913,221	815,882	690,270
Income from operations	140,837	129,072	138,685	110,151	92,475	72,897	64,007	57,929	518,745	287,308	206,107
Interest expense, net									(241,195)	(116,081)	(80,520)
Loss on extinguishment of debt									(34,882)
Other expenses									(1,284)	(555)	(517)
Income before income taxes	87,519	74,085	80,777	(997)	47,101	43,149	43,283	37,139	241,384	170,672	125,070
Income tax benefit (expense)									233,943	(77,572)	(48,687)
Net income (loss)									475,327	93,100	76,383
Net (income) loss attributable to noncontrolling interests									(330)	(1,563)	1,301
Net income attributable to Nexstar Media Group, Inc.	$ 378,481	$ 46,475	$ 43,992	$ 6,049	$ 20,482	$ 24,799	$ 24,529	$ 21,727	474,997	91,537	77,684
Net income									475,327	93,100	76,383
Other comprehensive income:
Change in unrecognized amounts included in pension and postretirement obligations, net of tax of $2,160									6,140
Total comprehensive income									481,467	93,100	76,383
Total comprehensive income attributable to noncontrolling interests									(330)	(1,563)	1,301
Total comprehensive income attributable to Nexstar Media Group, Inc.									481,137	91,537	77,684
Eliminations [Member]
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Revenue between consolidated entities									(146,286)	(89,308)	(74,986)
Net revenue									(146,286)	(89,308)	(74,986)
Operating expenses (income):
Direct operating expenses, excluding depreciation and amortization									(3,711)	(214)	(4)
Selling, general, and administrative expenses, excluding depreciation and amortization									(24,799)	(5,525)	(4,131)
Local service agreement fees between consolidated entities									(117,776)	(83,569)	(70,851)
Total operating expenses									(146,286)	(89,308)	(74,986)
Equity in income of subsidiaries									(471,363)	(72,193)	(59,256)
Income before income taxes									(471,363)	(72,193)	(59,256)
Net income (loss)									(471,363)	(72,193)	(59,256)
Net income attributable to Nexstar Media Group, Inc.									(471,363)	(72,193)	(59,256)
Net income									(471,363)	(72,193)	(59,256)
Other comprehensive income:
Total comprehensive income									(471,363)
Total comprehensive income attributable to Nexstar Media Group, Inc.									(471,363)	(72,193)	(59,256)
Nexstar [Member] | Reportable Legal Entities [Member]
Operating expenses (income):
Equity in income of subsidiaries									471,363	72,193	59,256
Income before income taxes									471,363	72,193	59,256
Net income (loss)									471,363	72,193	59,256
Net income attributable to Nexstar Media Group, Inc.									471,363	72,193	59,256
Net income									471,363	72,193	59,256
Other comprehensive income:
Total comprehensive income									471,363
Total comprehensive income attributable to Nexstar Media Group, Inc.									471,363	72,193	59,256
Nexstar Broadcasting [Member] | Reportable Legal Entities [Member]
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net broadcast revenue (including trade and barter)									2,160,330	939,333	759,694
Revenue between consolidated entities									71,434	34,436	25,854
Net revenue									2,231,764	973,769	785,548
Operating expenses (income):
Direct operating expenses, excluding depreciation and amortization									793,606	284,866	233,530
Selling, general, and administrative expenses, excluding depreciation and amortization									569,194	246,698	213,415
Local service agreement fees between consolidated entities									51,859	49,202	44,997
Amortization of broadcast rights									92,888	47,990	49,044
Amortization of intangible assets									137,808	27,394	29,312
Depreciation									91,791	45,173	41,833
Goodwill and intangible assets impairment										186
Gain on disposal of stations, net									(57,716)
Total operating expenses									1,679,430	701,509	612,131
Income from operations									552,334	272,260	173,417
Interest expense, net									(226,853)	(104,231)	(69,649)
Loss on extinguishment of debt									(32,523)
Other expenses									(1,284)	(555)	(517)
Income before income taxes									291,674	167,474	103,251
Income tax benefit (expense)									219,460	(69,149)	(39,851)
Net income (loss)									511,134	98,325	63,400
Net income attributable to Nexstar Media Group, Inc.									511,134	98,325	63,400
Net income									511,134	98,325	63,400
Other comprehensive income:
Change in unrecognized amounts included in pension and postretirement obligations, net of tax of $2,160									6,140
Total comprehensive income									517,274
Total comprehensive income attributable to Nexstar Media Group, Inc.									517,274	98,325	63,400
Mission [Member] | Reportable Legal Entities [Member]
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net broadcast revenue (including trade and barter)									70,592	61,402	51,132
Revenue between consolidated entities									36,580	42,930	37,135
Net revenue									107,172	104,332	88,267
Operating expenses (income):
Direct operating expenses, excluding depreciation and amortization									35,820	30,278	24,667
Selling, general, and administrative expenses, excluding depreciation and amortization									4,168	3,611	3,605
Local service agreement fees between consolidated entities									35,500	18,000	9,780
Amortization of broadcast rights									5,645	5,567	5,766
Amortization of intangible assets									2,422	2,544	2,540
Depreciation									2,342	2,400	2,435
Total operating expenses									85,897	62,400	48,793
Income from operations									21,275	41,932	39,474
Interest expense, net									(10,135)	(10,251)	(9,325)
Loss on extinguishment of debt									(2,133)
Income before income taxes									9,007	31,681	30,149
Income tax benefit (expense)									(3,400)	(12,337)	(12,172)
Net income (loss)									5,607	19,344	17,977
Net income attributable to Nexstar Media Group, Inc.									5,607	19,344	17,977
Net income									5,607	19,344	17,977
Other comprehensive income:
Total comprehensive income									5,607
Total comprehensive income attributable to Nexstar Media Group, Inc.									5,607	19,344	17,977
Non-Guarantors [Member] | Reportable Legal Entities [Member]
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net broadcast revenue (including trade and barter)									201,044	102,455	85,551
Revenue between consolidated entities									38,272	11,942	11,997
Net revenue									239,316	114,397	97,548
Operating expenses (income):
Direct operating expenses, excluding depreciation and amortization									167,690	67,067	44,064
Selling, general, and administrative expenses, excluding depreciation and amortization									43,423	18,822	19,591
Local service agreement fees between consolidated entities									30,417	16,367	16,074
Amortization of broadcast rights									6,870	3,588	5,026
Amortization of intangible assets									19,270	16,634	16,623
Depreciation									6,525	3,727	2,954
Goodwill and intangible assets impairment									19,985	15,076
Total operating expenses									294,180	141,281	104,332
Income from operations									(54,864)	(26,884)	(6,784)
Interest expense, net									(4,207)	(1,599)	(1,546)
Loss on extinguishment of debt									(226)
Income before income taxes									(59,297)	(28,483)	(8,330)
Income tax benefit (expense)									17,883	3,914	3,336
Net income (loss)									(41,414)	(24,569)	(4,994)
Net (income) loss attributable to noncontrolling interests									(330)	(1,563)	1,301
Net income attributable to Nexstar Media Group, Inc.									(41,744)	(26,132)	(3,693)
Net income									(41,414)	(24,569)	(4,994)
Other comprehensive income:
Total comprehensive income									(41,414)
Total comprehensive income attributable to noncontrolling interests									(330)
Total comprehensive income attributable to Nexstar Media Group, Inc.									$ (41,744)	$ (26,132)	$ (3,693)