Share-Based Compensation - Nonvested Restricted Shares (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Restricted Stock
Shares
Nonvested Restricted Shares, Beginning Balance (in shares) | shares	35,630
Granted (in shares) | shares	174,347
Vested (in shares) | shares	(208,196)
Forfeited (in shares) | shares	(1,781)
Nonvested Restricted Shares, Ending Balance (in shares) | shares	0
Weighted Avg. Grant Date Fair Value
Nonvested (in dollars per share) | $ / shares	$ 63.27
Granted (in dollars per share) | $ / shares	9.10
Vested (in dollars per share) | $ / shares	41.50
Forfeited (in dollars per share) | $ / shares	58.01
Nonvested (in dollars per share) | $ / shares	$ 0
Share-Settled RSUs
Shares
Nonvested Restricted Shares, Beginning Balance (in shares) | shares	1,125,346
Granted (in shares) | shares	1,897,780
Vested (in shares) | shares	(448,974)
Forfeited (in shares) | shares	(455,547)
Nonvested Restricted Shares, Ending Balance (in shares) | shares	2,118,605
Weighted Avg. Grant Date Fair Value
Nonvested (in dollars per share) | $ / shares	$ 37.91
Granted (in dollars per share) | $ / shares	7.66
Vested (in dollars per share) | $ / shares	41.37
Forfeited (in dollars per share) | $ / shares	32.54
Nonvested (in dollars per share) | $ / shares	$ 26.00
PSUs
Shares
Nonvested Restricted Shares, Beginning Balance (in shares) | shares	806,233
Granted (in shares) | shares	6,654
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(285,782)
Nonvested Restricted Shares, Ending Balance (in shares) | shares	527,105
Weighted Avg. Grant Date Fair Value
Nonvested (in dollars per share) | $ / shares	$ 34.12
Granted (in dollars per share) | $ / shares	12.26
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	28.98
Nonvested (in dollars per share) | $ / shares	$ 36.37