Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parentheticals) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Deferred income taxes	$ 1,733	$ 575	$ 1,406	$ 986
Changes in Fair Value of Marketable Securities [Member]
Deferred income taxes	(16)	(201)	639	285
Realized Gains on Marketable Securities [Member]
Deferred income taxes	0	(178)	(2)	(265)
Unrealized Losses on Marketable Securities [Member]
Deferred income taxes	$ (1)	$ 17	$ (10)	$ 17