Supplemental Quarterly Financial Data (Unaudited) (Quarterly Financial Information - Segment Reporting) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Net sales	$ 562,625	$ 494,810	$ 493,222	$ 487,646	$ 565,447	$ 524,284	$ 482,467	$ 429,042	$ 2,038,303	$ 2,001,240	$ 1,935,976
Interest expense, net	(7,289)	(5,858)	(5,108)	(5,822)	(4,503)	(5,899)	(6,128)	(6,003)	(24,077)	(22,533)	(26,430)
Consolidated earnings before income taxes	68,727	57,559	57,591	57,072	75,076	62,468	56,756	32,944	240,949	227,244	199,571
Total of Reporting Segments [Member]
Net sales									2,038,303	2,001,240	1,935,976
Segment earnings (loss)	89,494	76,981	72,852	75,061	92,121	79,560	72,177	49,620	314,388	293,478	265,062
Aerospace [Member]
Net sales	335,207	288,480	281,426	255,770	318,209	274,923	261,021	229,872	1,160,883	1,084,025	1,061,477
Segment earnings (loss)	59,964	46,362	45,628	35,793	57,005	39,357	40,289	22,549	187,747	159,200	166,122
Energy [Member]
Net sales	227,418	206,330	211,796	231,876	247,238	249,361	221,446	199,170	877,420	917,215	874,499
Segment earnings (loss)	29,530	30,619	27,224	39,268	35,116	40,203	31,888	27,071	126,641	134,278	98,940
Unallocated Corporate [Member]
Segment earnings (loss)	$ (13,478)	$ (13,564)	$ (10,153)	$ (12,167)	$ (12,542)	$ (11,193)	$ (9,293)	$ (10,673)	$ (49,362)	$ (43,701)	$ (39,061)