Other Financial Statement Details

Accounts Receivable

Accounts receivable consists of the following (amounts in thousands):



	September 30, 2017		March 31, 2017
Trade accounts receivable	$	539,569	$	473,238
Other	7,990		7,219
Total accounts receivable, gross	547,559		480,457
Less allowance for doubtful accounts	2,143		2,084
Total accounts receivable, net	$	545,416	$	478,373

Inventories

The components of inventories consist of the following (amounts in thousands):



	September 30, 2017		March 31, 2017
Raw materials	$	19,746	$	14,430
Work in process	296,941		268,281
Finished goods	140,252		134,491
Total inventories	$	456,939	$	417,202

Inventories are valued at the lower of cost and net realizable value using the first-in, first-out method. Inventory impairment charges establish a new cost basis for inventory and charges are not subsequently reversed to income even if circumstances later suggest that increased carrying amounts are recoverable.

Property, Plant and Equipment

Property, plant and equipment consists of the following (amounts in thousands):



	September 30, 2017		March 31, 2017
Land	$	73,446	$	73,447
Building and building improvements	501,974		499,668
Machinery and equipment	1,861,622		1,774,920
Projects in process	108,128		104,318
Total property, plant and equipment, gross	2,545,170		2,452,353
Less accumulated depreciation and amortization	1,822,390		1,769,015
Total property, plant and equipment, net	$	722,780	$	683,338

Depreciation expense attributed to property, plant and equipment was $29.9 million and $58.9 million for the three and six months ended September 30, 2017, respectively, compared to $30.0 million and $61.0 million for the three and six months ended September 30, 2016, respectively.