Acquisitions (Details) $ in Thousands	3 Months Ended		12 Months Ended		24 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) ft² item	Dec. 31, 2015 USD ($) ft² item	Dec. 31, 2016 USD ($) ft² item
Liabilities assumed:
Revenues	$ 198,720	$ 195,493
Net income (loss)	102,854	27,046
Depreciation and amortization	21,297	16,759
Gain (loss) on derivative financial instruments, net	(4,349)	$ (24,718)
Goodwill	140,437		$ 140,437		$ 140,437
Medical Office Portfolio
Acquisitions
Area of property | ft²			1,900,000		1,900,000
Number of acquired properties closed | item			34
Purchase price			$ 758,800
Liabilities assumed:
Bargain purchase gains			0
Goodwill			$ 0		$ 0
Woodstar Portfolio
Acquisitions
Number of properties in portfolio investment | item			32		32
Number of acquired properties closed | item			14	18	32
Number of units acquired | item			8,948
Purchase price					$ 421,500
Liabilities assumed:
Bargain purchase gains			$ 8,400
Goodwill			$ 0		$ 0
Ireland Portfolio
Acquisitions
Number of properties in portfolio investment | item				12
Area of property | ft²				600,000
Debt incurred to fund acquisition				$ 328,600
Assets acquired:
Total assets acquired				518,200
Liabilities assumed:
Total liabilities assumed				283,000
Bargain purchase gains				0
Goodwill				$ 0
REO Portfolio | ASU 2015-16
Assets acquired:
Properties	12,747
Intangible assets	3,468
Other assets	97
Total assets acquired	16,312
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities	1,397
Total liabilities assumed	1,397
Non-controlling interests	3,084
Net assets acquired	11,831
REO Portfolio | ASU 2015-16 | Initial Amount
Assets acquired:
Properties	12,087
Intangible assets	4,270
Other assets	97
Total assets acquired	16,454
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities	1,539
Total liabilities assumed	1,539
Non-controlling interests	3,084
Net assets acquired	11,831
REO Portfolio | ASU 2015-16 | Measurement Period Adjustments
Assets acquired:
Properties	660
Intangible assets	(802)
Total assets acquired	(142)
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities	(142)
Total liabilities assumed	$ (142)
Investment and Servicing Segment
Acquisitions
Number of real estate business acquired | item			10	14	24
Purchase price					$ 268,500
Liabilities assumed:
Bargain purchase gains			$ 8,800
Goodwill			$ 0		$ 0