CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Other comprehensive (loss) income, tax:
Reclassification adjustment for write-down of marketable securities included in net earnings, tax	$ 113	$ 0	$ 295	$ 0
Reclassification adjustment for gain on sale of marketable securities included in net earnings (loss), tax	0	0	0	45
Unrealized holding losses on marketable securities arising during the period, tax	(59)	(234)	(118)	(305)
Change in unfunded SERP liability, tax	$ 18	$ 0	$ 53	$ 0