Consolidated Statements of Changes in Stockholder's Equity - USD ($) $ in Thousands	Common Shares	Additional Paid-In Capital	Accumulated (Losses) Earnings	Noncontrolling Interests	Total
Balance at Jun. 30, 2019	$ 655	$ 2,201,773	$ (65,747)	$ 33,772	$ 2,170,453
Balance (in shares) at Jun. 30, 2019	65,440,492
Increase (Decrease) in Stockholders' Equity
Stock-based compensation and related share issuances		(323)			(323)
Stock-based compensation and related share issuances (in shares)	55,295
Distributions from (to) non-controlling interests		900		(192)	708
Net income (loss) and comprehensive income (loss)			70,453	(1,581)	68,872
Dividends declared			(17,382)		(17,382)
Balance at Sep. 30, 2019	$ 655	2,202,350	(12,676)	31,999	2,222,328
Balance (in shares) at Sep. 30, 2019	65,495,787
Balance at Jun. 30, 2020	$ 655	2,210,429	61,133	29,902	2,302,119
Balance (in shares) at Jun. 30, 2020	65,531,288
Increase (Decrease) in Stockholders' Equity
Stock-based compensation and related share issuances	$ 1	105			106
Stock-based compensation and related share issuances (in shares)	14,318
Sale of Peak Gold JV interest		(10,829)		(16,218)	(27,047)
Net income (loss) and comprehensive income (loss)			106,939	(265)	106,674
Distributions to non-controlling interests				(261)	(261)
Dividends declared			(18,370)		(18,370)
Balance at Sep. 30, 2020	$ 656	$ 2,199,705	$ 149,702	$ 13,158	$ 2,363,221
Balance (in shares) at Sep. 30, 2020	65,545,606