CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on cash flow hedges, tax expense (recovery)	$ (60,000)	$ (252,000)	$ 403,000	$ (380,000)
(Gain) loss reclassified into net income, tax (expense) recovery	(141,000)	(33,000)	(428,000)	(38,000)
Actuarial gain (loss), tax expense (recovery)	(153,000)	1,077,000	(236,000)	484,000
Amortization of actuarial (gain) loss into net income, tax (expense) recovery	43,000	57,000	85,000	119,000
Unrealized net gain (loss) on marketable securities, tax effect	0	0	0	0
Release of unrealized gain on marketable securities, tax effect	$ 0	$ 0	$ 0	$ 0