Note 8 - Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 30, 2017
Balance		$ 1,441,974	$ 927,556
Activity in the period		(279)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Balance	[1]	(10,839)	(10,836)
Cumulative effect adjustment (b)	[1],[2]
Activity in the period	[1]	(3)
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Balance			9,795
Cumulative effect adjustment (b)	[1],[2]	(9,795)
Activity in the period
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Balance		(62,903)	(62,627)
Cumulative effect adjustment (b)	[1],[2]
Activity in the period		(276)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Balance		(73,742)	$ (63,668)
Cumulative effect adjustment (b)	[1],[2]	(9,795)
Activity in the period		$ (279)

[1] The balances at March 31, 2018 and December 30, 2017 are net of taxes of $0.2 million and $1.4 million, respectively.

[2] The Company adopted ASU 2016-01 on December 31, 2018 on a modified retrospective basis, recognizing the cumulative effect as a $9.8 million increase to retained earnings. See Note 1, Summary of Significant Accounting Policies and Other Information, for further discussion.