Note 18 - Fair Value Measurements (Details) - Fair Value of Financial Assets Measure on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Available-for-sale securities:
Available-for-sale securities	$ 270,336	$ 212,277
Assets held in trading accounts	6,881	8,978
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Available-for-sale securities	3,994	3,985
US Treasury Securities [Member]
Available-for-sale securities:
Available-for-sale securities	3,994	3,985
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Available-for-sale securities	238,411	178,217
US Government Agencies Debt Securities [Member]
Available-for-sale securities:
Available-for-sale securities	238,411	178,217
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Available-for-sale securities	1,958	1,891
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale securities:
Available-for-sale securities	1,958	1,891
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Available-for-sale securities	6,920	7,861
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities:
Available-for-sale securities	6,920	7,861
Other Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities:
Other securities		1,504
Other Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Other securities	19,053	18,819
Other Securities [Member]
Available-for-sale securities:
Available-for-sale securities	19,053	20,323
Other securities	19,053	20,323
Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities:
Assets held in trading accounts	3,320	1,520
Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities:
Assets held in trading accounts	$ 3,561	$ 7,458