CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016
Costs and estimated earnings on long-term contracts, progress billings	$ 33,851	$ 31,129
Property, plant and equipment, net of accumulated depreciation	89,209	84,454
Intangible assets, net of accumulated amortization	60,604	56,955
Advance payments on long-term contracts, costs incurred	$ 41,760	$ 35,266
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	30,364,183	30,364,183
Treasury stock, shares	4,643,722	4,647,322