BENEFIT PLANS Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2013 Pension Plans, Defined Benefit	Jun. 30, 2012 Pension Plans, Defined Benefit	Jun. 30, 2013 Pension Plans, Defined Benefit	Jun. 30, 2012 Pension Plans, Defined Benefit	Sep. 30, 2012 Other Postretirement Benefit Plans, Defined Benefit	Jun. 30, 2012 Other Postretirement Benefit Plans, Defined Benefit	Jun. 30, 2013 Other Postretirement Benefit Plans, Defined Benefit	Jun. 30, 2012 Other Postretirement Benefit Plans, Defined Benefit
Service cost			$ 3,662	$ 3,032	$ 7,385	$ 6,010	$ 61	$ 18	$ 123	$ 37
Interest cost			2,445	2,627	4,922	5,318	122	118	243	235
Expected return on plan assets			(1,230)	(1,189)	(2,477)	(2,414)
Amortization of prior service cost			(33)	(33)	(67)	(70)
Amortization of net loss			1,269	494	2,549	992	88	57	176	115
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	(235)		(625)
Defined Benefit Plan, Net Periodic Benefit Cost			$ 5,878	$ 4,931	$ 11,687	$ 9,836	$ 271	$ 193	$ 542	$ 387