Restructuring (narrative) (detail) - USD ($)	3 Months Ended				9 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Dec. 27, 2014	Dec. 26, 2015	Dec. 27, 2014
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	$ 9,624,000	$ 15,000	$ (81,000)	$ 889,000	$ 9,558,000	$ 889,000
Midwest Plant [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Equipment Cost						1,376,000
MidwestPlant2 [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	9,634,000
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	104,000	15,000	(81,000)	533,000
Employee Severance [Member] | Midwest Plant [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring		$ 15,000	$ 81,000
Restructuring Equipment Cost						842,000
Employee Severance [Member] | MidwestPlant2 [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	104,000
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	7,814,000			40,000
Other Restructuring [Member] | Midwest Plant [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	(10,000)
Restructuring Equipment Cost						270,000
Other Restructuring [Member] | MidwestPlant2 [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	7,824,000
Long Lived Asset Charges [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	1,706,000			$ 316,000
Long Lived Asset Charges [Member] | Midwest Plant [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Equipment Cost						$ 264,000
Long Lived Asset Charges [Member] | MidwestPlant2 [Member]
Restructuring Cost and Reserve [Line Items]
Plant Restructuring	$ 1,706,000