3. Equipment Held for Operating Lease

As of December 31, 2018, the Company had a total lease portfolio of 244 engines and related equipment, 17 aircraft and 10 other leased parts and equipment with a net book value of $1,673.1 million. As of December 31, 2017, the Company had a total lease portfolio of 225 aircraft engines and related equipment, 16 aircraft and 7 other leased parts and equipment, with a net book value of $1,342.6 million.

A majority of the equipment is leased and operated internationally. Substantially all leases relating to this equipment are denominated and payable in U.S. dollars.

The Company leases equipment to lessees domiciled in eight geographic regions. The tables below set forth geographic information about the leased equipment grouped by domicile of the lessee (which is not necessarily indicative of the asset’s actual location):


	Years Ended December 31,
Lease rent revenue	2018		2017		2016
	(in thousands)
Region
Europe	$	70,842	$	50,789	$	44,650
Asia		40,717		34,169		34,524
United States		40,100		20,307		13,395
South America		11,338		11,958		11,504
Mexico		4,721		5,409		6,251
Canada		4,585		4,355		4,049
Middle East		3,286		3,360		3,674
Africa		20		22		1,848
Totals	$	175,609	$	130,369	$	119,895


	As of December 31,
Net book value of equipment held for operating lease	2018		2017
	(in thousands)
Region
Europe	$	624,913	$	444,938
Asia		368,690		258,501
United States		260,095		251,959
South America		118,508		111,999
Middle East		43,602		61,606
Mexico		33,795		34,399
Canada		18,792		28,977
Africa		2,597		2,959
Off-lease and other		202,143		147,233
Totals	$	1,673,135	$	1,342,571

As of December 31, 2018, the lease status of the equipment held for operating lease (in thousands) was as follows:


Lease Term	Net Book Value
Off-lease and other	$	202,143
Month-to-month leases		216,523
Leases expiring 2019		588,615
Leases expiring 2020		290,882
Leases expiring 2021		63,387
Leases expiring 2022		165,117
Leases expiring 2023		90,490
Leases expiring thereafter		55,978
	$	1,673,135

As of December 31, 2018, minimum future payments under non-cancelable leases were as follows:


Year	(in thousands)
2019	$	136,549
2020		68,565
2021		44,163
2022		30,017
2023		12,019
Thereafter		7,299
	$	298,612