Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on interest rate derivative instrument, tax	$ 0	$ 0	$ (550)
Deferred taxes on unrealized loss on investment securities	(41)	(13)	0
Loss reclassified from AOCI into income, tax	$ 372	$ 130	$ 50