Note 16 - Employee Benefit Plans - Target Asset Allocations (Details)	Jun. 30, 2018
UNITED STATES
Target asset allocations	100.00%
UNITED KINGDOM
Target asset allocations	100.00%
Equity Securities [Member] | UNITED STATES
Target asset allocations	32.00%
Equity Securities [Member] | UNITED KINGDOM
Target asset allocations	18.00%
Debt Securities [Member] | UNITED STATES
Target asset allocations	33.00%
Debt Securities [Member] | UNITED KINGDOM
Target asset allocations	45.00%
Hedge Funds, Global Opportunity [Member] | UNITED STATES
Target asset allocations	25.00%
Hedge Funds, Global Opportunity [Member] | UNITED KINGDOM
Target asset allocations	37.00%
Other Debt Obligations [Member] | UNITED STATES
Target asset allocations	10.00%
Other Debt Obligations [Member] | UNITED KINGDOM
Target asset allocations	0.00%