Consolidated Statements of Changes in Stockholder's Equity - USD ($) $ in Thousands	Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated (Losses) Earnings	Noncontrolling Interests	Total
Balance at Jun. 30, 2018	$ 654	$ 2,192,612	$ (1,201)	$ (89,898)	$ 39,102	$ 2,141,269
Balance (in shares) at Jun. 30, 2018	65,360,041
Increase (Decrease) in Stockholders' Equity
Stock-based compensation and related share issuances		1,852				1,852
Stock-based compensation and related share issuances (in shares)	36,298
Distributions from (to) non-controlling interests		2,790			(227)	2,563
Net income and comprehensive income				38,596	(3,575)	35,021
Other comprehensive loss			$ 1,201	(1,201)
Dividends declared				(33,735)		(33,735)
Balance at Dec. 31, 2018	$ 654	2,197,254		(86,238)	35,300	2,146,970
Balance (in shares) at Dec. 31, 2018	65,396,339
Balance at Sep. 30, 2018	$ 654	2,195,034		(92,465)	36,046	2,139,269
Balance (in shares) at Sep. 30, 2018	65,394,898
Increase (Decrease) in Stockholders' Equity
Stock-based compensation and related share issuances		1,380				1,380
Stock-based compensation and related share issuances (in shares)	1,441
Distributions from (to) non-controlling interests		840			(203)	637
Net income and comprehensive income				23,586	(543)	23,043
Dividends declared				(17,359)		(17,359)
Balance at Dec. 31, 2018	$ 654	2,197,254		(86,238)	35,300	2,146,970
Balance (in shares) at Dec. 31, 2018	65,396,339
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		891				891
Stock-based compensation and related share issuances (in shares)	55,512
Distributions from (to) non-controlling interests		2,700			(379)	2,321
Net income and comprehensive income				111,774	(2,488)	109,286
Dividends declared				(35,737)		(35,737)
Balance at Dec. 31, 2019	$ 655	2,205,364		10,290	30,905	2,247,214
Balance (in shares) at Dec. 31, 2019	65,496,004
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
Increase (Decrease) in Stockholders' Equity
Stock-based compensation and related share issuances		1,214				1,214
Stock-based compensation and related share issuances (in shares)	217
Distributions from (to) non-controlling interests		1,800			(187)	1,613
Net income and comprehensive income				41,321	(907)	40,414
Dividends declared				(18,355)		(18,355)
Balance at Dec. 31, 2019	$ 655	$ 2,205,364		$ 10,290	$ 30,905	$ 2,247,214
Balance (in shares) at Dec. 31, 2019	65,496,004