Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred shares	Common shares	Treasury shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings
Total shareholders' equity						$ (8,556)
Balance - Beginning of period at Dec. 31, 2014		$ 0	$ 27,222	$ (12,545)	$ 1,207,493	(8,556)	$ 2,372,972
Preferred shares issued		0
Offering expenses on preferred shares					0
Common shares issued, net			878		16,529
Repurchase of common shares				(1,047)	(259,383)
Share compensation expenses					38,341
Other comprehensive income (loss)	$ (4,013)					(4,013)
Amounts reclassified from accumulated other comprehensive loss						0
Net (loss) income	467,857						467,857
Net loss (income) attributable to noncontrolling interests	(92,964)						(92,964)
Dividends on preferred shares							0
Dividends on common shares							(113,809)
Balance - End of period at Dec. 31, 2015	3,638,975	0	28,100	(13,592)	1,002,980	(12,569)	2,634,056
Noncontrolling interests	154,662
Total shareholders' equity	3,793,637					(12,569)
Preferred shares issued		150,000
Offering expenses on preferred shares					(5,148)
Common shares issued, net			124		(7,825)
Repurchase of common shares				(784)	(211,891)
Share compensation expenses					42,907
Other comprehensive income (loss)	(10,647)					(10,647)
Amounts reclassified from accumulated other comprehensive loss						0
Net (loss) income	487,202						487,202
Net loss (income) attributable to noncontrolling interests	(123,363)						(123,363)
Dividends on preferred shares							(4,455)
Dividends on common shares							(116,804)
Balance - End of period at Dec. 31, 2016	3,838,291	150,000	28,224	(14,376)	821,023	(23,216)	2,876,636
Noncontrolling interests	165,977
Total shareholders' equity	4,004,268					(23,216)
Preferred shares issued		250,000
Offering expenses on preferred shares					(8,314)
Common shares issued, net			125		(11,703)
Repurchase of common shares				(92)	(26,476)
Share compensation expenses					40,111
Other comprehensive income (loss)	574					574
Amounts reclassified from accumulated other comprehensive loss	450					450
Net (loss) income	(404,902)						(404,902)
Net loss (income) attributable to noncontrolling interests	357,280						357,280
Dividends on preferred shares							(15,861)
Dividends on common shares							(124,411)
Balance - End of period at Dec. 31, 2017	3,895,072	$ 400,000	$ 28,349	$ (14,468)	$ 814,641	(22,192)	$ 2,688,742
Noncontrolling interests	16,718
Total shareholders' equity	$ 3,911,790					$ (22,192)