8. Commitments

The Company’s commercial real estate operations include the leasing of office buildings and industrial properties subject to leases with terms greater than one year. The leases expire at various dates through 2036. The following is a schedule of approximate future minimum rental income on non-cancelable operating leases as of December 31, 2017:


	Year ending
(in thousands)	December 31,

2018	$	180,321
2019		156,530
2020		139,250
2021		121,185
2022		92,803
Thereafter (2023-2036)		244,075
	$	934,164

The Company leases its corporate office space under an operating lease that commenced September 1, 2010. The lease was amended on October 25, 2016 to extend the lease through September 30, 2024. The lease has a five-year extension option. The lease includes a base annual rent and additional rent for the Company’s share of taxes and operating costs. Future minimum lease payments are as follows:


	Year ending
(in thousands)	December 31,
2018	$	404
2019		412
2020		421
2021		429
2022		438
Thereafter		787
	$	2,891

Rent expense was approximately $420,000, $411,000 and $408,000 for the years ended December 31, 2017, 2016 and 2015, respectively, and is included in general and administration expenses in the consolidated statements of income.

The Company has entered into the Sponsored REIT Loans described in Note 3, which provide for up to $79.5 million in borrowings of which $71.7 million have been drawn and were outstanding as of December 31, 2017. The Company anticipates that any advances made will be repaid at their maturity or earlier from long term financing of the underlying properties, cash flows of the underlying properties or some other capital events.