Revenue from Contracts with Customers Revenue, Initial Application Period Cumulative Effect Transition (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Mar. 30, 2019	Mar. 31, 2018	Apr. 01, 2017	Apr. 02, 2016
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accrued liabilities	$ 125,181				$ 126,500				$ 125,181	$ 126,500
Total current liabilities	174,008				176,329				174,008	176,329
Deferred income taxes	7,002				7,577				7,002	7,577
Retained earnings	280,078				209,381				280,078	209,381
Total stockholder's equity	529,588				457,106				529,588	457,106	$ 394,408	$ 353,226
Net revenue	241,113	$ 233,700	$ 241,530	$ 246,403	242,529	$ 221,383	$ 200,507	$ 206,816	962,746	871,235	773,797
Cost of sales									757,040	690,555	615,760
Gross profit	55,793	$ 49,021	$ 49,416	$ 51,476	$ 54,304	$ 49,856	$ 34,554	$ 41,966	205,706	180,680	158,037
Selling, general and administrative expense									121,568	106,907	101,231
Income from operations									84,138	73,773	56,806
Income before income taxes									86,676	78,523	55,281
Income tax expense									18,054	17,021	17,326
Net income									68,622	61,502	37,955
Difference between Revenue Guidance in Effect before and after Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accrued liabilities	1,750								1,750
Total current liabilities	1,750								1,750
Deferred income taxes	(461)								(461)
Retained earnings	(1,289)								(1,289)
Total stockholder's equity	(1,289)								(1,289)
Net revenue									(32,420)
Cost of sales									(31,047)
Gross profit									(1,373)
Selling, general and administrative expense									(289)
Income from operations									(1,084)
Income before income taxes									(1,084)
Income tax expense									(250)
Net income									(834)
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accrued liabilities	126,931								126,931
Total current liabilities	175,758								175,758
Deferred income taxes	6,541								6,541
Retained earnings	278,789								278,789
Total stockholder's equity	$ 528,299								528,299
Net revenue									930,326
Cost of sales									725,993
Gross profit									204,333
Selling, general and administrative expense									121,279
Income from operations									83,054
Income before income taxes									85,592
Income tax expense									17,804
Net income									67,788
Subcontracted site improvements
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue									$ 24,900	$ 21,200	$ 18,800