Intangible Assets (Tables)

6 Months Ended

Mar. 31, 2017

Intangible Assets

Schedule of gross carrying amounts and accumulated amortization of intangible assets

					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

Schedule of total currently estimated annual amortization expense

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