Transactions with Affiliates - Additional Information (Detail)			3 Months Ended		6 Months Ended
	Jul. 01, 2020	Jul. 01, 2012 $ / mo	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jul. 02, 2012 ft² $ / ft²
Related Party Transaction [Line Items]
Description of management fee					In exchange for these services, our Manager receives a management fee, paid monthly in arrears, in an amount equal to one-twelfth of 1.20% of our Equity (as defined in the Management Agreement).
Annual management fee as a percent of equity					1.20%
Number of days prior notice of non-renewal of the Management Agreement					180 days
Sublease agreement, square feet leased | ft²							7,300
Rent paid for leased office space per square foot | $ / ft²							71.50
New sublease agreement, base monthly rent | $ / mo		43,497.47
Sublease agreement, base monthly rent percentage increase starting July 1, 2017	3.00%
Rent			$ 143,000	$ 140,000	$ 287,000	$ 280,000
Stockholders equity amount used to calculate administrative service fees			225,000,000		$ 225,000,000
Prior written notice to terminate administrative agreement					30 days
Administrative service fees			$ 32,000	$ 47,000	$ 75,000	$ 96,000
First $225 million of Stockholders' Equity
Related Party Transaction [Line Items]
Basis points on equity for the annual fee					5.00%
Above $225 million of Stockholders' Equity
Related Party Transaction [Line Items]
Basis points on equity for the annual fee					2.25%
Mr. Lloyd McAdams
Related Party Transaction [Line Items]
Outstanding membership interests					47.40%
Mr. Joseph E. McAdams
Related Party Transaction [Line Items]
Outstanding membership interests					47.40%
Mr. Brett Roth
Related Party Transaction [Line Items]
Additional payment for change in control and arbitration agreements					$ 350,000
Ms. Heather U. Baines
Related Party Transaction [Line Items]
Outstanding membership interests					5.20%