Condensed Consolidated Statements of Changes in Members'/Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Members' Equity	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares/units) at Sep. 30, 2019		1,527
Beginning balance at Sep. 30, 2019		$ 149,383
Issuance of common units under long-term incentive plan (in units)		15
Purchase of common units under long-term incentive plan (in shares)		(2)
Purchase of common units under long-term incentive plan		$ (194)
Dividends on preferred units		(864)
Dividends on common units		(4,997)
Unit-based compensation expense		153
Net income (loss)		$ (6,841)
Ending balance (in shares/units) at Dec. 31, 2019		1,540
Ending balance at Dec. 31, 2019		$ 136,640
Beginning balance (in shares/units) at Sep. 30, 2019		1,527
Beginning balance at Sep. 30, 2019		$ 149,383
Dividends on preferred units	$ (1,741)
Net income (loss)	68,212
Common shares issued for business combination	0
Cash dividends declared	0
Ending balance (in shares/units) at Mar. 31, 2020		1,555
Ending balance at Mar. 31, 2020		$ 205,910
Beginning balance (in shares/units) at Dec. 31, 2019		1,540
Beginning balance at Dec. 31, 2019		$ 136,640
Issuance of common units under long-term incentive plan (in units)		16
Purchase of common units under long-term incentive plan (in shares)		(1)
Purchase of common units under long-term incentive plan		$ (124)
Dividends on preferred units		(877)
Dividends on common units		(4,988)
Unit-based compensation expense		206
Net income (loss)	75,053	$ 75,053
Ending balance (in shares/units) at Mar. 31, 2020		1,555
Ending balance at Mar. 31, 2020		$ 205,910
Beginning balance (in shares/units) at Sep. 30, 2020		1,555
Beginning balance at Sep. 30, 2020	0	$ 166,617
Issuance of common units under long-term incentive plan (in units)		13
Dividends on preferred units	0	$ (917)
Dividends on common units	0	(3,801)
Unit-based compensation expense	0	413
Net income (loss)	0	$ (7,941)
Ending balance (in shares/units) at Dec. 31, 2020		1,568
Ending balance at Dec. 31, 2020	0	$ 154,371
Beginning balance (in shares/units) at Sep. 30, 2020		1,555
Beginning balance at Sep. 30, 2020	0	$ 166,617
Dividends on preferred units	0
Net income (loss)	(59,819)
Common shares issued for business combination	26,392
Cash dividends declared	4,991
Ending balance (in shares/units) at Mar. 31, 2021		0	17,825
Ending balance at Mar. 31, 2021	181,240	$ 0	$ 18	$ 218,974	$ (37,752)
Beginning balance (in shares/units) at Dec. 31, 2020		1,568
Beginning balance at Dec. 31, 2020	0	$ 154,371
Purchase of common units under long-term incentive plan (in shares)		(3)
Purchase of common units under long-term incentive plan	0	$ 191
Preferred units converted to common units (in units)		512
Preferred units converted to common units	0	$ 61,196
Dividends on preferred units	0	(574)
Dividends on common units	0	(3,770)
Unit-based compensation expense	0	$ 276
Net income (loss)	(51,878)
Restricted common shares issued in exchange for common units issued under long-term incentive plan (in shares)		(24)	198
Common stock issued in exchange for common units (in shares)		(2,053)	16,733
Common stock issued in exchange for common units	192,191	$ (192,191)	$ 17	192,174
Common shares issued for business combination (in shares)			891
Common shares issued for business combination	26,392		$ 1	26,391
Restricted common shares issued			3
Share-based compensation expense	409			409
Cash dividends declared	4,991				4,991
Ending balance (in shares/units) at Mar. 31, 2021		0	17,825
Ending balance at Mar. 31, 2021	$ 181,240	$ 0	$ 18	$ 218,974	$ (37,752)