Basis Of Presentation And Consolidation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Mar. 31, 2013	Jun. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Stock-based compensation and related net tax benefits			$ 453	$ 1,504
(Increase) decrease in other operating assets, net			571	(2,839)	(3,479)
(Decrease) increase in accounts payable and other accrued liabilities	(3,328)	(3,963)	(2,025)	(2,959)	(1,157)	(596)	3,305	169
Net cash provided by operating activities	10,128	4,152	20,164	9,024	19,582	25,750	36,840	31,729
Cash flows used by investing activities:
Acquisition of property, plant and equipment	(1,245)	(3,714)	(2,415)	(5,962)	(8,135)	(9,145)	(14,519)	(13,415)
Net cash used by investing activities	(3,764)	(4,167)	(5,055)	(6,640)	(10,108)	(11,296)	(125,456)	(17,841)
Cash flows (used) provided by financing activities:
Long-term borrowings - loan			20,000	10,300	19,400
Net cash used by financing activities			(15,410)	(8,976)	(17,905)
As Previously Reported [Member]
Cash flows from operating activities:
(Increase) decrease in other operating assets, net				(3,039)	(3,679)
(Decrease) increase in accounts payable and other accrued liabilities	(3,502)	(5,775)		(4,310)	(4,006)	(3,389)	3,982	(323)
Net cash provided by operating activities	9,954	2,340		7,473	16,533	22,957	37,517	31,237
Cash flows used by investing activities:
Acquisition of property, plant and equipment	(1,071)	(1,902)		(4,611)	(5,286)	(6,352)	(15,196)	(12,923)
Net cash used by investing activities	(3,590)	(2,355)		(5,289)	(7,259)	(8,503)	(126,133)	(17,349)
Cash flows (used) provided by financing activities:
Long-term borrowings - loan				10,500	19,600
Net cash used by financing activities				(8,776)	(17,705)
Adjustment [Member]
Cash flows from operating activities:
(Increase) decrease in other operating assets, net				200	200
(Decrease) increase in accounts payable and other accrued liabilities	174	1,812		1,351	2,849	2,793	(677)	492
Net cash provided by operating activities	174	1,812		1,551	3,049	2,793	(677)	492
Cash flows used by investing activities:
Acquisition of property, plant and equipment	(174)	(1,812)		(1,351)	(2,849)	(2,793)	677	(492)
Net cash used by investing activities	(174)	(1,812)		(1,351)	(2,849)	(2,793)	677	(492)
Cash flows (used) provided by financing activities:
Long-term borrowings - loan				(200)	(200)
Net cash used by financing activities				$ (200)	$ (200)