Note 12 - Assets and Liabilities Measured and Reported at Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Securities available-for-sale	$ 1,006,908	$ 586,978
US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities available-for-sale	9,077
US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	154,980	138,078
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale	786,711	437,585
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	55,133	11,315
Other Debt Obligations [Member]
Securities available-for-sale	1,007
Fair Value, Recurring [Member]
Securities available-for-sale	1,006,908	586,978
Interest rate swaps	5,668	8,374
Total assets	1,012,576	595,352
Interest rate swaps	5,760	8,391
Fair Value, Recurring [Member] | US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities available-for-sale	9,077
Fair Value, Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	154,980	138,078
Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale	786,711	437,585
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	55,133	11,315
Fair Value, Recurring [Member] | Other Debt Obligations [Member]
Securities available-for-sale	1,007
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	9,077	0
Interest rate swaps	0	0
Total assets	9,077	0
Interest rate swaps	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities available-for-sale	9,077
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Debt Obligations [Member]
Securities available-for-sale	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	997,831	586,978
Interest rate swaps	5,668	8,374
Total assets	1,003,499	595,352
Interest rate swaps	5,760	8,391
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities available-for-sale	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	154,980	138,078
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale	786,711	437,585
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	55,133	11,315
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Debt Obligations [Member]
Securities available-for-sale	1,007
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale	0	0
Interest rate swaps	0	0
Total assets	0	0
Interest rate swaps	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities available-for-sale	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	0	$ 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Debt Obligations [Member]
Securities available-for-sale	$ 0