Property, Plant and Equipment (Tables)

12 Months Ended

Sep. 30, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets as follows:

Buildings	2 to 40 years
Building improvements	2 to 22 years
Machinery and production equipment	2 to 20 years
Support and testing machinery and equipment	2 to 15 years
Leasehold improvements	Lesser of remaining term of the lease or economic useful life

As of September 30, 2017 and September 30, 2016, property, plant and equipment at cost and accumulated depreciation were as follows:

(in thousands)	September 30, 2017			September 30, 2016
Land	$	13,296		$	12,804
Buildings and related improvements	105,154			103,256
Machinery and equipment	263,575			245,011
Leasehold improvements	6,744			6,498
Construction in progress	16,160			6,148
Property, plant and equipment	404,929			373,717
Accumulated depreciation	(196,310		)	(171,025		)
Property, plant and equipment, net	$	208,619		$	202,692