Basis of Presentation New Accounting Pronouncements (Details) - USD ($)	3 Months Ended			6 Months Ended
	Sep. 29, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Apr. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 195,488,000	$ 186,766,000	$ 136,788,000	$ 195,488,000	$ 136,788,000
Restricted cash	13,754,000	11,228,000	12,899,000	13,754,000	12,899,000
Restricted cash, Noncurrent	453,000	1,264,000	726,000	453,000	726,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	209,695,000	199,258,000	150,413,000	209,695,000	150,413,000	$ 144,839,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	6,200,000		$ 5,000,000	12,800,000	$ 10,100,000
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	454,000			454,000
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	1,621,000			1,621,000
Nonoperating Income (Expense) [Member] | Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (276,000)			1,400,000
Accrued Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 600,000		$ 2,007,000