Significant Accounting Policies - Recently Adopted Accounting Guidance (Details) - USD ($) $ in Thousands	Jan. 28, 2019	Jan. 27, 2019	Apr. 29, 2018	Jan. 28, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in retained earnings		$ 574,930		$ 502,346
Deferred income tax assets		14,362		4,236
Prepaid taxes		$ (8,406)		(11,809)
ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in retained earnings				$ 11,100
ASU 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in retained earnings			$ (1,600)
Deferred income tax assets			3,700
Prepaid taxes			$ 5,500
ASU 2016-02 | Scenario, Forecast | Subsequent Event | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	$ 10,000
Lease liabilities	10,000
ASU 2016-02 | Scenario, Forecast | Subsequent Event | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	15,000
Lease liabilities	$ 15,000