7. Intangible Assets

The gross carrying amounts and accumulated amortization of intangible assets are as follows at the dates indicated:



	September 29, 2018						September 30, 2017
(in thousands of dollars)	Gross Carrying Amount		Accumulated Amortization		Total		Gross Carrying Amount		Accumulated Amortization		Total
Finite lived: Engineering designs	$	982	$	280	$	702	$	982	$	141	$	841
Finite lived: Customer relationships	37,425		22,471		14,954		37,425		20,601		16,824
Total amortized intangible assets	38,407		22,751		15,656		38,407		20,742		17,665
Indefinite lived: Trade name	39,816		—		39,816		39,816		—		39,816
Total intangible assets	$	78,223	$	22,751	$	55,472	$	78,223	$	20,742	$	57,481

Management considers the "Blue Bird" trade name to have an indefinite useful life and, accordingly, it is not subject to amortization. Management reached this conclusion principally due to the longevity of the Blue Bird name and because management considers renewal upon reaching the legal limit of the trademarks related to the trade name as perfunctory. The Company expects to maintain usage of the trade name on existing products and introduce new products in the future that will also display the trade name. During the fourth quarters of the fiscal years ended 2018 and 2017, we performed our annual impairment assessment of our trade name, which did not indicate that an impairment existed; therefore, no impairments of our indefinite lived intangibles have been recorded.

Customer relationships are amortized on a straight-line basis over an estimated life of 20 years. Engineering designs are amortized on a straight-line basis over an estimated life of 7 years. Total amortization expense for intangible assets was $2.0 million, $2.0 million, and $1.9 million for the fiscal years ended 2018, 2017, and 2016, respectively.

Amortization expense for finite lived intangible assets for the next five years is expected to be as follows:



Fiscal Years Ending	Amortization Expense
2019	$	2,009
2020	2,009
2021	2,009
2022	2,009
2023	2,009
Thereafter	5,611
Total amortization expense	$	15,656