Comprehensive Income, Reclassification Out of AOCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 84,058		$ 49,184
Income tax (expense) benefit	(33,275)		(18,694)
Net income	50,783		30,490		122,824
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(10,074)	[1],[2]	(7,736)	[1],[2]
Income tax (expense) benefit	3,828	[1],[2]	2,940	[1],[2]
Net income	(6,246)	[1],[2]	(4,796)	[1],[2]
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension Costs [Member] | Prior-service Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(2)	[1],[2]	50	[1],[2]
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension Costs [Member] | Actuarial Gains/(Losses) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(10,072)	[1],[2]	(7,786)	[1],[2]
Reclassification out of Accumulated Other Comprehensive Income [Member] | Postretirement Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(703)	[1],[2]	592	[1],[2]
Income tax (expense) benefit	267	[1],[2]	(225)	[1],[2]
Net income	(436)	[1],[2]	367	[1],[2]
Reclassification out of Accumulated Other Comprehensive Income [Member] | Postretirement Costs [Member] | Prior-service Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	1,525	[1],[2]	2,503	[1],[2]
Reclassification out of Accumulated Other Comprehensive Income [Member] | Postretirement Costs [Member] | Actuarial Gains/(Losses) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ (2,228)	[1],[2]	$ (1,911)	[1],[2]

[1] These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 16 - Retirement Plans for additional details).

[2] Amounts in parentheses indicate losses.