Intangible Assets

6 Months Ended

Mar. 31, 2017

5.Intangible Assets

The following table summarizes the gross carrying amounts and related accumulated amortization of intangible assets as of:


					September 30, 2016				March 31, 2017
					Gross				Gross
	Estimated				Carrying		Accumulated		Carrying		Accumulated
(in thousands of dollars)	useful lives				Amount		Amortization		Amount		Amortization
Trade names	Indefinite				$	63,245	$	—	$	62,574	$	—
Intellectual property			20	years		10,102		—		10,026		654
Contracts	15	-	20	years		127,520		76,029		125,130		76,697
Customer relationships	5	-	20	years		227,909		67,493		226,779		73,912
Trade names			20	years		66,755		39,744		66,755		41,413
Patents and patented technologies	7	-	19	years		5,401		2,875		6,347		3,180
Other	5	-	17	years		7,035		2,664		7,549		3,000
					$	507,967	$	188,805	$	505,160	$	198,856

The above table includes preliminary amounts for some of the intangible assets acquired in 2016 and 2017 because the process of identifying and valuing those assets has not been completed. Total amortization expense related to intangible assets was approximately $4.8 million and $6.4 million for the March 2016 and 2017 quarters, respectively, and approximately $9.4 million and $12.7 million for the six months ended March 31, 2016 and 2017, respectively.

Total estimated annual amortization expense for 2017 through 2022 is shown in the following table; however, the amounts will change once the intangible assets for the 2016 and 2017 acquisitions are identified and valuations are finalized.


Year ending September 30:	(in thousands)
2017	$	24,716
2018		24,928
2019		23,906
2020		19,802
2021		19,687
2022		19,436