Intangible Assets

6 Months Ended

Mar. 31, 2015

6.Intangible Assets

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

		September 30, 2014				March 31, 2015
(in thousands of dollars)	Estimated useful lives	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Trade names	Indefinite	$	15,300	$	—	$	15,300	$	—

CCP contracts	15 - 20 years	112,300		64,192		112,300		67,033
Customer relationships	5 - 17 years	107,953		50,355		109,299		54,188
Trade names	5 - 20 years	67,220		33,394		67,220		35,104
Patents and patented technologies	5 - 19 years	14,526		11,686		14,526		12,130
Other	5 - 17 years	3,935		1,744		4,584		1,962
		$	321,234	$	161,371	$	323,229	$	170,417

Total amortization expense related to intangible assets was approximately $5.5 million and $4.6 million for the March 2014 and 2015 quarters, respectively, and approximately $10.6 million and $9.0 million for the six months ended March 31, 2014 and 2015, respectively. The primary reason for the decrease in amortization expense from 2014 to 2015 is that certain assets have been fully amortized.

Total estimated annual amortization expense for 2015 through 2020 is shown in the following table:

Year ending September 30:	(in thousands)
2015	$	18,166
2016	17,957
2017	17,079
2018	17,030
2019	16,001
2020	11,762