The capitalized costs incurred during the period (excluded from amortization) to purchase, lease or otherwise acquire an unproved property, including costs of lease bonuses and options to purchase or lease properties, the portion of costs applicable to minerals when land including mineral rights is purchased in fee, brokers' fees, recording fees, legal costs, and other costs incurred in acquiring properties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-10(c)(7)(ii))
-URI http://asc.fasb.org/extlink&oid=82851474&loc=d3e511914-122862

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-10(c)(3)(ii)(A))
-URI http://asc.fasb.org/extlink&oid=82851474&loc=d3e511914-122862

Land, Building and Improvements and Assets Held for Sale - Narratives (Details) $ in Thousands			3 Months Ended		12 Months Ended
	Mar. 15, 2018 USD ($) property	Feb. 21, 2018 USD ($)	Mar. 31, 2018 USD ($) property tenant	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) property
Real Estate Properties
Increase in value of balance sheet item due to foreign currency translation			$ 18,516	$ 14,750
Investments in real estate
Purchases of real estate			85,197	0
Capitalized construction cost			$ 16,800
Number of construction projects \| property			4		5
Unfunded commitment			$ 130,700		$ 147,900
Carrying value of assets held for sale			33,182		0
Assets held for sale included in disposal group			$ 33,182		0
Held-for-sale
Investments in real estate
Number of real estate properties \| property			1
Number of properties sold \| property			4
In-place lease
Investments in real estate
Purchases of real estate			$ 13,100
Finite lived intangible assets useful life			24 years 4 months 26 days
Above-market rent
Investments in real estate
Purchases of real estate			$ 500
Finite lived intangible assets useful life			14 years 3 months 20 days
Education facility in Houston, TX
Investments in real estate
Capitalized construction cost					$ 18,300
Construction in progress placed into service			$ 21,100
Operating Lease
Real Estate Properties
Increase in value of balance sheet item due to foreign currency translation			41,900
Depreciation			37,200	35,400
Investments in real estate
Purchases of real estate			85,200
Acquisition related costs			200
Decrease in carrying value of real estate			$ 19,400
Number of tenants \| tenant			1
Purchase option exercise price, value			$ 8,000
Carrying value of assets held for sale			6,300
Operating Lease \| Land
Investments in real estate
Purchases of real estate			6,500
Operating Lease \| Building
Investments in real estate
Purchases of real estate			65,100
Operating Lease \| Net Lease Intangible
Investments in real estate
Purchases of real estate			$ 13,600
Operating Lease \| Sellersburg, Indiana
Investments in real estate
Purchases of real estate		$ 6,100
Operating Lease \| Properties in Wisconsin
Investments in real estate
Purchases of real estate	$ 79,100
Operating Lease \| Properties in Wisconsin \| Warehouse
Investments in real estate
Number of real estate properties \| property	1
Operating Lease \| Properties in Wisconsin \| Retail site
Investments in real estate
Number of real estate properties \| property	2
Hotel
Investments in real estate
Number of real estate properties \| property			1		2
Operating Properties
Real Estate Properties
Depreciation			$ 1,100	$ 1,100
EUR
Real Estate Properties
Increase in exchange rate			2.70%
Foreign currency exchange rate			1.2321		1.1993