Segments Disclosure - Schedule of Each Reportable Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Revenues
Rental income	$ 143,243
Tenant reimbursement income	13,488
Fee and other income	4,495
Total revenues	161,226
Total expenses	148,080
Operating income	13,146
Income from real estate fund investments	5,221
Income from partially owned entities	975
Unrealized gains on interest rate swaps	11,978
Interest and other income, net	854
Interest and debt expense	(41,888)
Acquisition and transaction related costs	(1,139)
Net income (loss) before income taxes	(10,853)
Income tax expense	(574)
Net income (loss)	(11,427)
Depreciation and amortization	73,583
General and administrative expenses	12,613
Interest and debt expense	41,888
Acquisition and transaction related costs	1,139
Income tax expense	574
NOI from partially owned entities	3,781
Income from real estate fund investments	(5,221)
Income from partially owned entities	(975)
Fee income	(1,535)
Unrealized gains on interest rate swaps	(11,978)
Interest and other income, net	(854)
Net operating income	101,588
Owned Properties [Member]
Revenues
Rental income	142,477
Tenant reimbursement income	13,488
Fee and other income	2,955
Total revenues	158,920
Total expenses	135,651
Operating income	23,269
Income from partially owned entities	940
Unrealized gains on interest rate swaps	11,978
Interest and other income, net	94
Interest and debt expense	(39,132)
Net income (loss) before income taxes	(2,851)
Income tax expense	(460)
Net income (loss)	(3,311)
Depreciation and amortization	73,337
General and administrative expenses	42
Interest and debt expense	39,132
Income tax expense	460
NOI from partially owned entities	3,736
Income from partially owned entities	(940)
Unrealized gains on interest rate swaps	(11,978)
Interest and other income, net	(94)
Net operating income	100,384
Other [Member]
Revenues
Rental income	766
Fee and other income	1,540
Total revenues	2,306
Total expenses	12,429
Operating income	(10,123)
Income from real estate fund investments	5,221
Income from partially owned entities	35
Interest and other income, net	760
Interest and debt expense	(2,756)
Acquisition and transaction related costs	(1,139)
Net income (loss) before income taxes	(8,002)
Income tax expense	(114)
Net income (loss)	(8,116)
Depreciation and amortization	246
General and administrative expenses	12,571
Interest and debt expense	2,756
Acquisition and transaction related costs	1,139
Income tax expense	114
NOI from partially owned entities	45
Income from real estate fund investments	(5,221)
Income from partially owned entities	(35)
Fee income	(1,535)
Interest and other income, net	(760)
Net operating income	$ 1,204