Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2017

Property, plant and equipment are stated at cost, net of accumulated depreciation. Depreciation expense is computed based on the straight-line method and charged to results of operations to allocate the cost of the assets over their estimated useful lives, as follows:


Buildings		10 - 40 years
Computer equipment and software		3 - 7 years
Machinery and equipment		2 - 10 years
Furniture and fixtures		3 - 10 years

Summary of Amortizable Lives of Intangible Assets

Finite-lived intangible assets are amortized over their useful lives, as follows:


Patents		7 - 15 years
Completed technology		3 - 10 years
Customer relationships		3 - 11 years

Stock-Based Compensation Expense

The following table reflects stock-based compensation expense, excluding amounts related to discontinued operations, recorded during the fiscal years ended September 30, 2017, 2016 and 2015 (in thousands):


	Year Ended September 30,
	2017		2016		2015
Restricted stock	$	16,662	$	11,220	$	11,696
Employee stock purchase plan		616		517		463
Total stock-based compensation expense	$	17,278	$	11,737	$	12,159

Fair Value of Shares Issued under Employee Stock Purchase Plan Estimated using Black-Scholes Option Pricing Model

The fair value of shares issued under the employee stock purchase plan is estimated on the commencement date of each offering period using the Black-Scholes option-pricing model with the following weighted average assumptions for the fiscal years ended September 30, 2017, 2016 and 2015:


	Year Ended September 30,
	2017		2016		2015
Risk-free interest rate	0.9	%	0.4	%	0.1	%
Volatility	34	%	32	%	31	%
Expected life	6 months		6 months		6 months
Dividend yield	3.4	%	3.4	%	3.4	%