Real Estate and Lending Activities - Summary of Status Update on Current Development Projects (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Business Acquisition [Line Items]
Commitment	$ 71,288
Costs Incurred as of 09/30/2017	28,008
Ernest [Member] | Flagstaff, Arizona [Member]
Business Acquisition [Line Items]
Commitment	28,067
Costs Incurred as of 09/30/2017	$ 16,619
Estimated Completion Date	1Q 2018
Circle [Member] | Birmingham, England [Member]
Business Acquisition [Line Items]
Commitment	$ 43,221
Costs Incurred as of 09/30/2017	$ 11,389
Estimated Completion Date	1Q 2019