Summary of Significant Accounting Policies (Tables)

6 Months Ended

Mar. 31, 2017

Accounting Policies [Abstract]

Schedule of Nonvested Restricted Stock Units Activity

As of March 31, 2017, the following annual equity grants for executive officers or a portion thereof are outstanding:

Grant Date	RSUs Granted	Vesting Schedule	Vesting Period	Date Fully Vested
November 1, 2016	115,347	Quarterly	4 years	November 1, 2020
November 2, 2015	145,508	Quarterly	4 years	November 1, 2019
November 1, 2014	171,575	Quarterly	4 years	November 1, 2018
November 1, 2013	231,320	Quarterly	4 years	November 1, 2017

Schedule of Computation of Basic and Diluted Net Income Per Share

The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share data):

	Three months ended March 31,				Six months ended March 31,
	2017		2016		2017		2016
Numerator
Net income	$	93,138	$	75,415	$	187,356	$	165,131
Denominator
Weighted average shares outstanding — basic	64,479		67,549		64,841		68,557
Dilutive effect of common shares from stock options and restricted stock units	549		255		548		324
Weighted average shares outstanding — diluted	65,028		67,804		65,389		68,881
Basic net income per share	$	1.44	$	1.12	$	2.89	$	2.41
Diluted net income per share	$	1.43	$	1.11	$	2.87	$	2.40