Note 11. Investments - Supplemental Employee Retirement Plan Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018
Schedule of Trading Securities and Other Trading Assets
SERP investments	$ 11,425	$ 12,114
SERP obligation	11,425	12,114
Short-term Investments
Schedule of Trading Securities and Other Trading Assets
SERP investments	3,188	3,868
SERP obligation	3,188	3,868
Other Long-term Investments
Schedule of Trading Securities and Other Trading Assets
SERP investments	8,237	8,246
SERP obligation	$ 8,237	$ 8,246

Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26626-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

Name:	us-gaap_TradingSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant