Short-Term and Long-Term Investments (Tables)

6 Months Ended

Mar. 31, 2017

Schedule of Investments [Line Items]

Schedule of Amortized Cost and Fair Value of Fixed Maturities by Contractual Years-To-Maturity

The amortized cost and fair value of fixed maturities at March 31, 2017, by contractual years-to-maturity, are presented below (in thousands):

	Cost or Amortized Cost		Fair Value
One year or less	$	359,128	$	358,851
Over one year	200,696		200,253
	$	559,824	$	559,104

Schedule of Investments That Have Been in a Continuous Unrealized Loss Position

The following table summarizes investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for more than 12 months as of March 31, 2017 (in thousands):

	Less Than 12 Months					12 Months or Greater					Total
March 31, 2017	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds and notes	$	164,402	$	(383	)	$	60,125	$	(62	)	$	224,527	$	(445	)
Municipal bonds and notes	45,514		(49		)	12,557		(7		)	58,071		(56		)
U.S. government securities	93,900		(120		)	4,998		(1		)	98,898		(121		)
U.S. government agency securities	64,638		(226		)	—		—			64,638		(226		)
Total	$	368,454	$	(778	)	$	77,680	$	(70	)	$	446,134	$	(848	)

Short-Term Investments [Member]

Schedule of Investments [Line Items]

Schedule of Short-Term and Long-Term Investments

Short-term investments consist of the following (in thousands):

March 31, 2017	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposits	$	1,993	$	1	$	—		$	1,994
Corporate bonds and notes	206,977		25		(182		)	206,820
Municipal bonds and notes	56,119		7		(23		)	56,103
U.S. government securities	92,039		—		(104		)	91,935
U.S. government agency securities	2,000		—		(1		)	1,999
	$	359,128	$	33	$	(310	)	$	358,851

September 30, 2016	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds and notes	$	223,448	$	38	$	(128	)	$	223,358
Municipal bonds and notes	53,657		1		(37		)	53,621
U.S. government securities	72,497		31		(7		)	72,521
U.S. government agency securities	18,318		6		—			18,324
	$	367,920	$	76	$	(172	)	$	367,824

Long-Term Investments [Member]

Schedule of Investments [Line Items]

Schedule of Short-Term and Long-Term Investments

Long-term investments consist of the following (in thousands):

March 31, 2017	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds and notes	$	86,085	$	33	$	(263	)	$	85,855
Municipal bonds and notes	39,528		56		(33		)	39,551
U.S. government securities	8,971		2		(17		)	8,956
U.S. government agency securities	66,112		4		(225		)	65,891
	$	200,696	$	95	$	(538	)	$	200,253

September 30, 2016	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds and notes	$	131,273	$	249	$	(95	)	$	131,427
Municipal bonds and notes	27,017		46		(13		)	27,050
U.S. government securities	26,989		36		(2		)	27,023
U.S. government agency securities	90,877		52		(54		)	90,875
	$	276,156	$	383	$	(164	)	$	276,375