Shareholders' Equity - Narrative (Details) - USD ($)				1 Months Ended	3 Months Ended
	Jun. 15, 2017	Nov. 25, 2015	Aug. 22, 2012	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020	Mar. 03, 2021	Dec. 31, 2020	Feb. 21, 2017
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				150,000,000	150,000,000
Common stock, shares issued (in shares)				91,954,619	91,954,619			89,815,175
Common stock, shares outstanding (in shares)				86,141,057	86,141,057			84,801,161
Preference shares issued (in shares)				18,600,000	18,600,000
Preference shares outstanding (in shares)				18,600,000	18,600,000
Undesignated shares (in shares)				39,445,381	39,445,381
Preference shares outstanding, held by non-affiliates (in shares)				9,157,912	9,157,912
Stock repurchased, authorized amount (up to)									$ 100,000,000
Stock repurchase program, remaining authorized repurchase amount				$ 74,245,000	$ 74,245,000			$ 74,245,000
Payments for repurchase of redeemable preferred stock				$ 97,393,000
Gain from repurchase of preference shares					$ 62,450,000	$ 0
Shares repurchased for tax withholding (in shares)					799,548	0
Shares repurchased for tax withholding, price per share (in dollars per share)					$ 2.95
Treasury shares repurchased (in shares)					0	0
Preference shares - Series A, C and D
Class of Stock [Line Items]
Stock repurchased, authorized amount (up to)							$ 100,000,000
Preferences shares - Series A
Class of Stock [Line Items]
Shares redeemed (in shares)				2,561,636
Dividend rate			8.25%
Redemption price (in dollars per share)				$ 14.88	$ 14.88
Preference Shares - Series C
Class of Stock [Line Items]
Shares redeemed (in shares)				2,028,961
Dividend rate		7.125%
Redemption price (in dollars per share)				$ 14.65	14.65
Preference Shares - Series D
Class of Stock [Line Items]
Shares redeemed (in shares)				2,023,896
Dividend rate	6.70%
Redemption price (in dollars per share)				$ 14.60	$ 14.60