BUSINESS SEGMENT INFORMATION (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Business segment financial data
Sales	$ 425,917	$ 347,806	$ 338,834	$ 318,488	$ 396,366	$ 340,357	$ 354,492	$ 307,137	$ 1,431,045	$ 1,398,352	$ 1,361,407
Long-lived assets, net	78,700				65,400				78,700	65,400	59,700
United States
Business segment financial data
Sales									765,000	749,900	741,700
Long-lived assets, net	65,800				49,800				65,800	49,800	43,900
United Kingdom
Business segment financial data
Sales									282,400	294,400	267,400
Long-lived assets, net	8,600				9,300				8,600	9,300	9,200
Canada
Business segment financial data
Sales									17,600	9,000	30,400
Australia
Business segment financial data
Sales									164,600	161,900	148,500
Middle East
Business segment financial data
Sales									67,700	42,000	35,400
Far East
Business segment financial data
Sales									55,300	76,600	78,200
Other foreign countries
Business segment financial data
Sales									78,400	64,600	59,800
Long-lived assets, net	$ 4,300				$ 6,300				$ 4,300	$ 6,300	$ 6,600