D. Detail of Selected Balance Sheet Accounts

Allowance for Doubtful Accounts

Activity in our allowance for doubtful accounts consisted of the following (in thousands):

	September 30,
	2015			2014
Balance at beginning of period	$	1,577		$	572
Bad debt expense (recovery)		(29	)		1,074
Uncollectible accounts written off, net of recoveries		(749	)		(58	)
Change in foreign currency translation		(53	)		(11	)
Balance at end of period	$	746		$	1,577

Inventories

The components of inventories are summarized below (in thousands):

	September 30,
	2015			2014
Raw materials, parts and subassemblies	$	36,575		$	35,349
Work-in-progress		1,084			2,035
Provision for excess and obsolete inventory		(4,768	)		(4,569	)
Total inventories	$	32,891		$	32,815

Cost and Estimated Earnings on Uncompleted Contracts

The components of costs and estimated earnings and related amounts billed on uncompleted contracts are summarized below (in thousands):

	September 30,
	2015			2014
Costs incurred on uncompleted contracts	$	912,237		$	604,939
Estimated earnings		271,640			157,562
		1,183,877			762,501
Less: Billings to date		(1,121,141	)		(715,233	)
Net underbilled position	$	62,736		$	47,268

Included in the accompanying balance sheets under the following captions:
Costs and estimated earnings in excess of billings on uncompleted contracts – underbilled	$	104,793		$	95,970
Billings in excess of costs and estimated earnings on uncompleted contracts – overbilled		(42,057	)		(48,702	)
Net underbilled position	$	62,736		$	47,268

Property, Plant and Equipment

Property, plant and equipment are summarized below (in thousands):

	September 30,						Range of
	2015			2014			Asset Lives
Land	$	22,380		$	23,545		—
Buildings and improvements		120,983			100,901		3 - 39 Years
Machinery and equipment		100,306			100,922		3 - 15 Years
Furniture and fixtures		3,564			3,852		3 - 10 Years
Construction in process		1,013			15,878		—
	$	248,246		$	245,098
Less: Accumulated depreciation		(93,652	)		(88,202	)
Total property, plant and equipment, net	$	154,594		$	156,896

The increase in buildings and improvements was primarily the completion of the expansion of our facility in Acheson, Alberta, Canada in Fiscal 2015.

There were no assets under capital lease as of September 30, 2015 or September 30, 2014. Depreciation expense from continuing operations, including the depreciation of capital leases when applicable, was $13.1 million, $11.4 million and $8.5 million for fiscal years 2015, 2014, and 2013, respectively.

Warranty Accrual

Activity in our product warranty accrual consisted of the following (in thousands):

	September 30,
	2015			2014
Balance at beginning of period	$	4,557		$	5,282
Increase to warranty expense		3,364			3,237
Deduction for warranty charges		(2,738	)		(3,892	)
Increase (decrease) due to foreign currency translations		(253	)		(70	)
Balance at end of period	$	4,930		$	4,557