Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Sep. 30, 2017

Summary of Changes in the Company's Goodwill

A summary of changes in the Company’s goodwill during the fiscal years ended September 30, 2017 and 2016 are as follows (in thousands):

Balance as of September 30, 2015	$	211,045
Fiscal year 2016 business combinations		1,715
Balance as of September 30, 2016		212,760
Fiscal year 2017 business combinations		13,155
Balance as of September 30, 2017	$	225,915

Intangible Assets Subject to Amortization

Intangible assets subject to amortization consist of the following (in thousands):

	September 30,
	2017								2016
	Gross Carrying Amount		Accum. Amortization		Net		Gross Carrying Amount		Accum. Amortization		Net
Customer lists	$	346,784	$	264,632	$	82,152	$	327,388	$	250,427	$	76,961
Trade names and other intangibles		32,047		8,981		23,066		27,134		6,439		20,695
Total	$	378,831	$	273,613	$	105,218	$	354,522	$	256,866	$	97,656

Estimated Annual Amortization Expense Related to Intangible Assets Subject to Amortization

Total estimated annual amortization expense related to intangible assets subject to amortization, for the year ended September 30, 2018 and the four succeeding fiscal years ended September 30, is as follows (in thousands):

	Amount
2018	$	18,483
2019	$	16,859
2020	$	15,095
2021	$	12,374
2022	$	10,349