Income taxes - Summary of Activity Related to Unrecognized Tax Benefits, Excluding Federal Tax Benefit of State Tax Deductions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 28, 2014
Change in unrecognized tax benefits
Balance at beginning of year	$ 19,491	$ 58,886	$ 57,324
Additions based on tax positions related to the current year	213	6,095	12,426
Additions for tax positions of prior years	162	853	868
Reductions for tax positions of prior years	(1,214)	(24,858)	(4,563)
Settlements	0	0	(129)
Reductions for transfers to Gannett Co., Inc.	0	(18,804)	0
Reductions due to lapse of statutes of limitations	(1,352)	(2,681)	(7,040)
Balance at end of year	$ 17,300	$ 19,491	$ 58,886