Note 6 - Pension and Post-retirement Benefits (Detail) - Net periodic benefit costs for postretirement medical plan (Postretirement Medical Plan [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Postretirement Medical Plan [Member]
Service cost	$ 127	$ 96	$ 383	$ 288
Interest cost	136	155	409	467
Amortization of prior service credit	(185)	(226)	(557)	(679)
Amortization of accumulated loss	40	4	119	14
	$ 118	$ 29	$ 354	$ 90

Note 6 - Pension and Post-retirement Benefits (Detail) - Net periodic benefit costs for postretirement medical plan (Postretirement Medical Plan [Member], USD $)
In Thousands, unless otherwise specified

3 Months Ended

9 Months Ended

Mar. 31, 2013

Mar. 31, 2012

Mar. 31, 2013

Mar. 31, 2012

Postretirement Medical Plan [Member]

Service cost

$ 127

$ 96

$ 383

$ 288

Interest cost

136

155

409

467

Amortization of prior service credit

(185)

(226)

(557)

(679)

Amortization of accumulated loss

119

$ 118

$ 29

$ 354

$ 90

- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ References+ Details

- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph a, h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Service Cost (Component of Net Periodic Pension Cost)

-URI http://asc.fasb.org/extlink&oid=6525008

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 106

-Paragraph 518

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (h)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

+ Details