Stock-Based Compensation

6 Months Ended

Mar. 01, 2014

Stock-Based Compensation [Abstract]

Stock-Based Compensation

Note 3. Stock-Based Compensation

The Company accounts for all share-based payments in accordance with ASC Topic 718, "Compensation—Stock Compensation" ("ASC 718").  The stock‑based compensation expense related to the stock option plans and the Associate Stock Purchase Plan included in operating expenses was $1,741and $1,329 for the thirteen week periods ended March 1, 2014 and March 2, 2013, respectively, and $3,196 and $2,768for the twenty-six week periods ended March 1, 2014 and March 2, 2013, respectively.  Tax benefits related to these expenses for the thirteen week periods endedMarch 1, 2014 and March 2, 2013were $637 and $480, respectively, and for the twenty-six week periods ended March 1, 2014 and March 2, 2013were $1,163 and $1,004, respectively.

The fair value of each option grant is estimated on the date of grant using the Black‑Scholes option pricing model with the following assumptions:

	Twenty-Six Weeks Ended
	March 1,		March 2,
	2014		2013
Expected life (in years)	3.9		3.8
Risk-free interest rate	0.93	%	0.55	%
Expected volatility	26.59	%	32.86	%
Expected dividend yield	1.70	%	1.70	%

A summary of the Company’s stock option activity for the twenty-sixweeks ended March 1, 2014is as follows:

	Options	Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding on August 31, 2013	1,224	$	58.30
Granted	399		81.76
Exercised	(255)		47.85
Canceled	(17)		72.46
Outstanding on March 1, 2014	1,351	$	67.02	5.29	$	15,204
Exercisable on March 1, 2014	486	$	55.77	3.99	$	10,242

The weighted‑average grant-date fair values of the stock options granted for the twenty-six week periods ended March 1, 2014and March 2, 2013were $14.98 and $15.33, respectively.  The unrecognized share‑based compensation cost related to stock option expense at March 1, 2014 was $10,557and will be recognized over a weighted average period of 1.8 years. The total intrinsic value of options exercised, which represents the difference between the exercise price and market value of common stock measured at each individual exercise date, during the twenty-six week periods ended March 1, 2014and March 2, 2013 were $9,113 and $12,356, respectively.

A  summary of the non‑vested restricted share award activity under the Company’s 2005 Omnibus Incentive Plan (the “Plan”) for the twenty-six weeks ended March 1, 2014 is as follows:

	Shares	Weighted-Average  Grant-Date Fair Value
Non-vested restricted share awards at August 31, 2013	505	$	59.47
Granted	121		82.20
Vested	(147)		51.18
Canceled/Forfeited	(11)		67.54
Non-vested restricted share awards at March 1, 2014	468	$	68.33

Stock‑based compensation expense recognized for the restricted share awards was $2,753 and $1,992 for the thirteen week periods ended March 1, 2014 and March 2, 2013, respectively, and $4,990 and $4,277 for the twenty-six week periods ended March 1, 2014 and March 2, 2013, respectively.The unrecognized compensation cost related to restricted share awards granted under the Plan at March 1, 2014 was $20,027 and will be recognized over a weighted average period of 2.4 years. 

A summary of the Company’s non-vested restricted stock unit award activity including dividend equivalent units for the twenty-six weeks ended March 1, 2014is as follows:

	Shares		Weighted- Average Grant- Date Fair Value
Non-vested restricted stock unit awards at August 31, 2013	196	$	55.32
Granted	2		80.82
Vested	—		—
Canceled/Forfeited	—		—
Non-vested restricted stock unit awards at March 1, 2014	198	$	55.60

Stock‑based compensation expense recognized for the restricted stock units was $542 and $529 for the thirteen week periods ended March 1, 2014 and March 2, 2013, respectively, and$1,081 and$1,059 for the twenty-six week periods ended March 1, 2014 and March 2, 2013, respectively.  The unrecognized compensation cost related to the restricted stock units at March 1, 2014was $2,917 and is expected to be recognized over a period of 1.9years.