Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($) Property Tenant	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Accounting Policies [Line Items]
Accumulated amortization of long-term debt financing costs	$ 5,100,000				$ 6,900,000						$ 5,100,000	$ 6,900,000
Number of tenants paying entity leasehold income potentially taxable under tax rules | Tenant	5
Number of properties treated as foreclosure properties | Property	2
Income tax expense	$ (4,424,000)	$ 3,070,000	$ 0	$ 0	663,000	$ 8,449,000	$ 666,000	$ 0	$ 666,000	$ 9,115,000	(1,354,000)	9,778,000	$ 0
Property operating expenses					27,586,000	56,531,000	52,296,000	37,698,000	89,994,000	146,525,000	$ 80,881,000	174,111,000	$ 190,165,000
Adjustment | 2015 Insurance Reserve
Accounting Policies [Line Items]
Income tax expense					663,000	8,449,000	666,000	0	666,000	9,115,000		9,778,000
Property operating expenses					$ 274,000	$ 275,000	$ 275,000	$ 660,000	$ 935,000	$ 1,210,000		$ 1,484,000
Minimum
Accounting Policies [Line Items]
Percentage of taxable income and capital gains required to be distributed not to be subjected to federal corporate income taxes											100.00%
Building and Building Improvements | Maximum
Accounting Policies [Line Items]
Depreciation period for property											39 years