Consolidated Statement Of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-in Capital [Member]	Treasury shares [Member]	Accumulated other comprehensive income (loss) [Member]	Distributions in excess of net income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 2,185,901	$ 663	$ 139	$ 2,677,046	$ (113,172)	$ 7,734	$ (386,509)
Balance (in shares) at Dec. 31, 2016		66,263,487	13,849,050
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Changes During Period Shares		19,030
Issuance of nonvested shares, net		295,754
Issuance of nonvested shares, net	(5,498)	$ (3)		(5,585)	90
Purchase of common shares for vesting	6,729				6,729
Amortization of nonvested shares	(6,600)			(6,600)
Share option expense	361			361
Foreign currency translation adjustment	6,222					6,222
Change in unrealized gain/loss on derivatives	(4,258)					(4,258)
Net income	134,451						134,451
Issuances of common shares (in shares)		935,638
Issuances of common shares	68,477	$ 9		68,468
Stock Issued During Period, Shares, Acquisitions		8,851,264
Stock Issued During Period, Value, Acquisitions	$ 657,473	$ 89		657,384
Stock Issued During Period, Shares, Conversion of Convertible Securities		61
Stock Redeemed or Called During Period, Shares			(135)
Stock option exercises, net (in shares)	28,175	28,175
Stock option exercises, net	$ 0	$ 0		(1,542)	(1,542)
Dividends to common and preferred shareholders	(152,650)						(152,650)
Balance (in shares) at Jun. 30, 2017		76,393,409	13,848,915
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 2,901,346	$ 764	$ 139	$ 3,416,986	$ (121,533)	$ 9,698	$ (404,708)