PENSION, PROFIT SHARING AND OTHER BENEFIT PLANS - Fair value by asset category and hierarchy (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Cash and cash equivalents
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	$ 3,071	$ 1,754
Cash and cash equivalents | Level 1
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	1,496	766
Cash and cash equivalents | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	1,575	988
Defined Benefit Pension Plans
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	194,253	201,502	$ 206,982
Defined Benefit Pension Plans | Level 1
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	1,496	766
Defined Benefit Pension Plans | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	185,196	192,570
Defined Benefit Pension Plans | Level 3
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	7,561	8,166	$ 7,096
Defined Benefit Pension Plans | Equity securities | United States
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	35,589	38,912
Defined Benefit Pension Plans | Equity securities | United States | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	35,589	38,912
Defined Benefit Pension Plans | Equity securities | Other foreign countries
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	48,288	45,120
Defined Benefit Pension Plans | Equity securities | Other foreign countries | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	48,288	45,120
Defined Benefit Pension Plans | Fixed-income funds | United States
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	46,292	49,744
Defined Benefit Pension Plans | Fixed-income funds | United States | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	46,292	49,744
Defined Benefit Pension Plans | Fixed-income funds | United Kingdom
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	25,927	24,707
Defined Benefit Pension Plans | Fixed-income funds | United Kingdom | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	25,927	24,707
Defined Benefit Pension Plans | Diversified growth fund
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	27,525	33,099
Defined Benefit Pension Plans | Diversified growth fund | Level 2
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	27,525	33,099
Defined Benefit Pension Plans | Real Estate
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	7,561	8,166
Defined Benefit Pension Plans | Real Estate | Level 3
Fair value of assets of defined benefit pension plans by asset category
Fair value of the assets	$ 7,561	$ 8,166