Stock-Based Compensation (Tables)

6 Months Ended

Jun. 27, 2020

Share-based Payment Arrangement [Abstract]

Schedule of stock-based compensation expense under all share-based payment plans [Table Text Block]

Stock-based compensation expense under all share-based payment plans -- our Employee Stock Purchase Plan, stock option plans, stock-settled stock appreciation rights ("SSARs") and restricted stock units ("RSUs") -- was included in the results of operations as follows:

	Three Months Ended				Six Months Ended
	June 27, 2020		June 29, 2019		June 27, 2020		June 29, 2019
Compensation expense, all share-based payment plans	$	964	$	776	$	1,709	$	1,529

Schedule of share-based compensation, stock-settled stock appreciation rights award activity [Table Text Block]

The following table summarizes our SSARs as of June 27, 2020.

Stock-Settled Stock Appreciation Rights	Number of Rights		Weighted- Average Award Date Value		Weighted- Average Remaining Contractual Life	Unrecognized Compensation Cost		Aggregate Intrinsic Value
Unvested, January 1, 2020	262,705		$	3.47
Granted	—		—
Forfeited	(2,254	)	3.53
Vested	(119,255	)	3.32
Unvested, June 27, 2020	141,196		$	3.60	1.4 years	$	377	$	3,417

Schedule of share-based compensation, restricted stock units award activity [Table Text Block]

The following table summarizes PRSUs and RSUs as of June 27, 2020.

Restricted Stock Units	Number of Stock Units		Weighted- Average Grant Date Value		Weighted- Average Remaining Contractual Life	Unrecognized Compensation Cost		Aggregate Intrinsic Value
Unvested, January 1, 2020	224,259		$	17.11
Granted	98,863		23.74
Forfeited	(1,871	)	17.37
Vested	(65,944	)	15.52
Unvested, June 27, 2020	255,307		$	20.09	2.9 years	$	3,335	$	6,178
Employee PRSUs	220,157		$	19.92	3.2 years	$	2,842	$	5,328
Nonemployee Director RSUs	35,150		$	21.14	1.9 years	$	493	$	851

Schedule of share-based payment award, stock options, valuation assumptions [Table Text Block]

The fair values of stock-based awards granted were estimated at the dates of grant with the following weighted-average assumptions.

	Six Months Ended
	June 27, 2020		June 29, 2019
Volatility rate	9.7	%	9.9	%
Risk-free interest rate	.7	%	2.3	%
Expected dividend yield	.4	%	.7	%
Expected life of awards (years)	8.1		8.8

Schedule of share-based compensation, stock options activity [Table Text Block]

The following table summarizes activity under the stock option plans for the six months ended June 27, 2020.

Stock Options	Number of Options Outstanding		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life	Aggregate Intrinsic Value
Outstanding, January 1, 2020	1,428,082		$	15.13
Granted	174,897		24.20
Exercised	(57,469	)	11.48
Forfeited	(8,335	)	15.46
Outstanding, June 27, 2020	1,537,175		$	16.29	5.8 years	$	12,159
Exercisable, June 27, 2020	1,060,493		$	14.17	4.6 years	$	10,637