Share and Unit-Based Plans - Nonvested equity awards (Details)	3 Months Ended
	Mar. 31, 2021 $ / shares shares
Units
Granted (in shares)	1,581,451
LTIP Units
Units
Balance at beginning of period (in shares)	784,052
Granted (in shares)	1,581,451
Vested (in shares)	(16,467)
Forfeited (in shares)	0
Balance at end of period (in shares)	2,349,036
Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 28.11
Granted (in dollars per share) | $ / shares	10.15
Vested (in dollars per share) | $ / shares	29.86
Forfeited (in dollars per share) | $ / shares	0
Balance at end of period (in dollars per share) | $ / shares	$ 16.01
Phantom Stock Units
Units
Balance at beginning of period (in shares)	4,662
Granted (in shares)	14,566
Vested (in shares)	(5,691)
Forfeited (in shares)	0
Balance at end of period (in shares)	13,537
Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 35.35
Granted (in dollars per share) | $ / shares	10.96
Vested (in dollars per share) | $ / shares	16.33
Forfeited (in dollars per share) | $ / shares	0
Balance at end of period (in dollars per share) | $ / shares	$ 17.10
Stock Units
Units
Balance at beginning of period (in shares)	309,845
Granted (in shares)	92,057
Vested (in shares)	(72,407)
Forfeited (in shares)	(987)
Balance at end of period (in shares)	328,508
Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 21.47
Granted (in dollars per share) | $ / shares	13.43
Vested (in dollars per share) | $ / shares	34.41
Forfeited (in dollars per share) | $ / shares	22.12
Balance at end of period (in dollars per share) | $ / shares	$ 16.36