Income Taxes - Unrecognized Tax Benefit Rollforward (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jan. 27, 2018	Jan. 26, 2019	Jul. 29, 2017	Jul. 30, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns
Balance at beginning of year	$ 3,072	$ 3,322	$ 2,440	$ 2,327
Additions based on tax positions related to the fiscal year	283	444	441	161
Additions (reductions) based on tax positions related to prior years		77	229	86
Additions (reductions) based on tax positions related to prior years	33
Reductions related to the expiration of statutes of limitation	0	(57)	(38)	(134)
Balance at end of year	$ 3,322	$ 3,786	$ 3,072	$ 2,440

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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