Investments (Real Estate Investments) - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) Restaurant Marina	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Restaurant Marina	Sep. 30, 2016 USD ($)	Dec. 31, 2016 Restaurant Marina
Schedule of Investments [Line Items]
Depreciation and amortization expenses under real estate investments	$ 324	$ 303	$ 896	$ 987
Real Estate Investments [Member]
Schedule of Investments [Line Items]
Number of restaurants | Restaurant	1		1		1
Number of marinas | Marina	2		2		2
Depreciation and amortization expenses under real estate investments	$ 374	$ 126	$ 1,062	$ 314