Consolidated Statements of Income and Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Reclassifications for unrealized net gains on available-for-sale securities	$ 4,513	$ 5,085	$ 6,812
Reclassification adjustment for employee benefit costs	7,468	3,072	5,868
Reclassification adjustment, tax	$ 1,034	$ (704)	$ (331)