Note 17 - Fair Values of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($)		Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities		$ 328,060,000	$ 346,992,000
Reported Value Measurement [Member]
Available-for-sale Securities	[1]	328,060,000	346,992,000
Federal Home Loan Bank stock	[2]	8,026,000	7,567,000
Reported Value Measurement [Member] | Interest Rate Swap [Member]
Interest rate swap	[1]	84,000	253,000
Estimate of Fair Value Measurement [Member]
Available-for-sale Securities	[1]	328,060,000	346,992,000
Federal Home Loan Bank stock	[2]	8,026,000	7,567,000
Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member]
Interest rate swap	[1]	84,000	253,000
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities		0
Fair Value, Inputs, Level 1 [Member] | Reported Value Measurement [Member]
Cash		11,493,000	12,496,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Cash		11,493,000	12,496,000
Fair Value, Inputs, Level 2 [Member] | Reported Value Measurement [Member]
Cash equivalents		172,103,000	77,395,000
Bank owned life insurance		67,198,000	58,971,000
Accrued interest receivable		7,714,000	7,836,000
Deposits		2,374,985,000	2,275,382,000
Securities sold under agreements to repurchase		131,710,000	154,771,000
Federal Home Loan Bank advances		175,000,000	68,000,000
Subordinated debentures		44,835,000	55,154,000
Accrued interest payable		1,592,000	1,479,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Cash equivalents		172,103,000	77,395,000
Bank owned life insurance		67,198,000	58,971,000
Accrued interest receivable		7,714,000	7,836,000
Deposits		2,286,548,000	2,208,724,000
Securities sold under agreements to repurchase		131,710,000	154,771,000
Federal Home Loan Bank advances		174,734,000	68,858,000
Subordinated debentures		45,220,000	55,760,000
Accrued interest payable		1,592,000	1,479,000
Fair Value, Inputs, Level 3 [Member] | Reported Value Measurement [Member]
Loans, net		2,360,659,000	2,262,046,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Loans, net		$ 2,354,311,000	$ 2,261,026,000

[1] See Note 11 for a description of the fair value hierarchy as well as a disclosure of levels for classes of financial assets and liabilities.

[2] It is not practical to determine the fair value of FHLBI stock due to transferability restrictions.