RETIREMENT PLANS (Tables)

9 Months Ended

Jun. 30, 2018

Retirement Benefits [Abstract]

Schedule of components of net periodic benefit cost

The following tables detail the components of net periodic benefit cost for Barnwell’s retirement plans:

	Pension Plan						SERP						Postretirement Medical
	Three months ended June 30,
	2018			2017			2018			2017			2018		2017
Service cost (credit)	$	54,000		$	34,000		$	10,000		$	(5,000	)	$	—	$	—
Interest cost	88,000			78,000			19,000			1,000			19,000		22,000
Expected return on plan assets	(147,000		)	(122,000		)	—			—			—		—
Amortization of prior service cost (credit)	2,000			2,000			(1,000		)	(2,000		)	—		—
Amortization of net actuarial loss	25,000			21,000			3,000			(17,000		)	2,000		47,000
Net periodic benefit cost	$	22,000		$	13,000		$	31,000		$	(23,000	)	$	21,000	$	69,000

	Pension Plan						SERP						Postretirement Medical
	Nine months ended June 30,
	2018			2017			2018			2017			2018		2017
Service cost	$	162,000		$	178,000		$	30,000		$	26,000		$	—	$	—
Interest cost	266,000			252,000			57,000			42,000			57,000		66,000
Expected return on plan assets	(443,000		)	(404,000		)	—			—			—		—
Amortization of prior service cost (credit)	5,000			4,000			(4,000		)	(4,000		)	—		—
Amortization of net actuarial loss	74,000			103,000			10,000			—			8,000		141,000
Net periodic benefit cost	$	64,000		$	133,000		$	93,000		$	64,000		$	65,000	$	207,000