Acquisitions - Schedule of Unaudited Pro Forma Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Smadex
Pro Forma:
Total revenue	$ 307,805	$ 541,663
Net income (loss)	$ 13,133	$ 175,765
Basic and diluted earnings per share:
Net income per share, basic	$ 0.15	$ 1.95
Net income per share, diluted	$ 0.15	$ 1.91
Weighted average common shares outstanding, basic	89,115,997	90,272,257
Weighted average common shares outstanding, diluted	90,328,583	91,891,957
Headway
Pro Forma:
Total revenue		$ 545,592	$ 288,710
Net income (loss)		$ 176,138	$ 20,282
Basic and diluted earnings per share:
Net income per share, basic		$ 1.95	$ 0.23
Net income per share, diluted		$ 1.92	$ 0.22
Weighted average common shares outstanding, basic		90,272,257	89,340,589
Weighted average common shares outstanding, diluted		91,891,957	91,303,056
KMIR-TV and KPSE-LD
Pro Forma:
Total revenue		$ 543,355	$ 267,614
Net income (loss)		$ 176,299	$ 21,574
Basic and diluted earnings per share:
Net income per share, basic		$ 1.95	$ 0.24
Net income per share, diluted		$ 1.92	$ 0.24
Weighted average common shares outstanding, basic		90,272,257	89,340,589
Weighted average common shares outstanding, diluted		91,891,957	91,303,056