TRANSITION PERIOD COMPARATIVE DATA - Cash Flow (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income and comprehensive income	$ 138,828	$ 166,662	$ 302,776	$ 196,250	$ 89,079
Adjustments to reconcile net income and comprehensive income to net cash provided by operating activities:
Depreciation, depletion and amortization	99,685	94,245	183,569	175,434	163,056
Amortization of debt issuance costs	1,089	574	1,148	1,136	15,288
Gain on sale of Peak Gold JV interest		(33,906)	(33,906)
Non-cash employee stock compensation expense	3,218	2,892	5,730	9,116	6,617
Fair value changes in equity securities	1,350	(2,158)	(6,017)	(1,418)	6,800
Deferred tax expense (benefit)	2,510	(8,405)	456	(32,399)	(1,745)
Other	1	(176)	(177)	(148)	(2)
Changes in assets and liabilities:
Royalty receivables	(6,846)	(16,627)	(19,552)	(6,957)	5,623
Stream inventory	6,077	(2,229)	(6,014)	(291)	(2,069)
Income tax receivable	(396)	(6,504)	(2,085)	268	(2,663)
Prepaid expenses and other assets	(1,374)	900	318	(7,828)	2,793
Accounts payable	76	(549)	3,237	(275)	(6,426)
Income tax payable	4,591	9,995	1,156	6,349	(11,281)
Uncertain tax positions	(910)	(12,160)	(24,518)	(11,146)	3,180
Other liabilities	884	1,510	1,030	11,320	(15,084)
Net cash provided by operating activities	248,783	194,064	407,151	340,752	253,166
Cash flows from investing activities:
Acquisition of stream and royalty interests	(281,066)	(48,832)	(168,147)	(155,985)	(1,055)
Khoemacau subordinated debt facility	(7,000)		(18,000)
Proceeds from sale of Peak Gold JV interest		49,154	49,154
Proceeds from sale of Contango shares		12,146	12,146
Other	(64)	(364)	(541)	3,126	(4,540)
Net cash used in investing activities	(288,130)	12,104	(116,737)	(152,859)	(5,595)
Cash flows from financing activities:
Repayment of debt	(100,000)	(105,000)	(305,000)	(115,000)	(370,000)
Borrowings from revolving credit facility	100,000			200,000	220,000
Net payments from issuance of common stock	(921)	(1,415)	(1,465)	(4,180)	(1,595)
Common stock dividends	(39,374)	(36,735)	(76,099)	(71,471)	(67,477)
Other	(2,723)	(287)	(1,062)	2,411	2,226
Net cash (used in) provided by financing activities	(43,018)	(143,437)	(383,626)	11,760	(216,846)
Net (decrease) increase in cash and equivalents	(82,365)	62,731	(93,212)	199,653	30,725
Cash and equivalents at beginning of period	225,916	319,128	319,128	119,475	88,750
Cash and equivalents at end of period	$ 143,551	$ 381,859	$ 225,916	$ 319,128	$ 119,475