Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred shares	Common shares	Treasury shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings
Balance - Beginning of period at Dec. 31, 2016		$ 150,000	$ 28,224	$ (14,376)	$ 821,023	$ (23,216)	$ 2,876,636
Preferred shares issued		250,000
Common shares issued (redeemed), net			115		(12,076)
Repurchase of common shares				(47)	(13,949)
Offering expenses on preferred shares					(8,314)
Share compensation expenses					20,637
Other comprehensive (loss) income	$ 3,292					3,292
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net (loss) income	286,284						286,284
Net (income) attributable to noncontrolling interests	(86,222)						(86,222)
Dividends on common shares							(62,174)
Dividends on preferred shares							(4,406)
Balance - End of period at Jun. 30, 2017	4,211,431	400,000	28,339	(14,423)	807,321	(19,924)	3,010,118
Noncontrolling interests at Jun. 30, 2017	415,658
Total shareholders' equity at Jun. 30, 2017	4,627,089
Balance - Beginning of period at Mar. 31, 2017						(22,453)
Other comprehensive (loss) income	2,529
Net (loss) income	146,948
Net (income) attributable to noncontrolling interests	(43,650)
Balance - End of period at Jun. 30, 2017	4,211,431	400,000	28,339	(14,423)	807,321	(19,924)	3,010,118
Noncontrolling interests at Jun. 30, 2017	415,658
Total shareholders' equity at Jun. 30, 2017	4,627,089
Balance - Beginning of period at Dec. 31, 2017	3,895,072	400,000	28,349	(14,468)	814,641	(22,192)	2,688,742
Preferred shares issued		0
Common shares issued (redeemed), net			209		(24,128)
Repurchase of common shares				0	0
Offering expenses on preferred shares					0
Share compensation expenses					25,769
Other comprehensive (loss) income	31,202					31,202
Amounts reclassified from accumulated other comprehensive income (loss)						849
Net (loss) income	54,903						54,903
Net (income) attributable to noncontrolling interests	(100,223)						(100,223)
Dividends on common shares							(62,861)
Dividends on preferred shares							(11,656)
Balance - End of period at Jun. 30, 2018	3,809,136	400,000	28,558	(14,468)	816,282	9,859	2,568,905
Noncontrolling interests at Jun. 30, 2018	371,257
Total shareholders' equity at Jun. 30, 2018	4,180,393
Balance - Beginning of period at Mar. 31, 2018						9,405
Other comprehensive (loss) income	640
Amounts reclassified from accumulated other comprehensive income (loss)						(186)
Net (loss) income	(11,559)
Net (income) attributable to noncontrolling interests	(35,511)
Balance - End of period at Jun. 30, 2018	3,809,136	$ 400,000	$ 28,558	$ (14,468)	$ 816,282	$ 9,859	$ 2,568,905
Noncontrolling interests at Jun. 30, 2018	371,257
Total shareholders' equity at Jun. 30, 2018	$ 4,180,393