Operating Leases

12 Months Ended

Dec. 31, 2017

Operating lease expense incurred primarily for manufacturing and office space, machinery, and equipment was $38.6 million, $40.3 million, and $40.6 million in 2017, 2016, and 2015, respectively.

Minimum annual lease payments for noncancelable operating leases in effect at December 31, 2017 are as follows (in thousands):



2018	$	22,440
2019	18,006
2020	13,787
2021	11,001
2022	8,561
Thereafter	23,494
	$	97,289

Certain of our operating leases include step rent provisions and rent escalations. We include these step rent provisions and rent escalations in our minimum lease payments obligations and recognize them as a component of rental expense on a straight-line basis over the minimum lease term.