Shareholders' equity - Earnings Per Share (Basic and Diluted) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Income from continuing operations	$ 401,340	$ 447,962	$ 309,120
Income (loss) from discontinued operations, net of tax	4,325	(232,916)	178,879
Net loss (income) attributable to noncontrolling interests from discontinued operations	0	58,698	(51,302)
Net income attributable to TEGNA Inc.	$ 405,665	$ 273,744	$ 436,697
Weighted average number of common shares outstanding - basic	216,184	215,587	216,358
Effect of dilutive securities
Weighted average number of common shares outstanding - diluted	216,621	217,478	219,681
Earnings from continuing operations per share - basic (in dollars per share)	$ 1.86	$ 2.08	$ 1.43
Earnings from discontinued operations per share - basic (in dollars per share)	0.02	(0.81)	0.59
Net income per share - basic (in dollars per share)	1.88	1.27	2.02
Earnings from continuing operations per share - diluted (in dollars per share)	1.85	2.06	1.41
Earnings from discontinued operations per share - diluted (in dollars per share)	0.02	(0.80)	0.58
Net income per share - diluted (in dollars per share)	$ 1.87	$ 1.26	$ 1.99
Restricted Stock
Effect of dilutive securities
Effect of dilutive securities (in shares)	139	659	1,424
Performance Shares
Effect of dilutive securities
Effect of dilutive securities (in shares)	97	550	997
Stock Options
Effect of dilutive securities
Effect of dilutive securities (in shares)	201	682	902