Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Trading equity securities [Abstract]
SERP money market fund	$ 790		$ 790		$ 783
SERP mutual funds	3,043		3,043		2,813
Preferred stocks	1,168		1,168		1,170
Short-term investments in mutual funds					16,073
Trading debt securities [Abstract]
Corporate bonds	5,100		5,100		4,851
Municipal bonds	1,901		1,901		1,908
Floating rate notes	426		426		549
U.S. Treasury bonds and bills	225		225		250
Other	1,107		1,107		864
Derivative financial instruments	460		460		452
Total financial assets	14,220		14,220		29,713
Financial Liabilities [Abstract]
SERP liabilities	7,922		7,922		7,828
Total financial liabilities	7,922		7,922		7,828
Net unrealized gains (losses) incurred	(132)	656	(161)	553
Level 1 [Member]
Trading equity securities [Abstract]
SERP money market fund	790		790		783
SERP mutual funds	3,043		3,043		2,813
Preferred stocks	1,168		1,168		1,170
Short-term investments in mutual funds					16,073
Trading debt securities [Abstract]
Corporate bonds	3,966		3,966		3,696
Municipal bonds	0		0		0
Floating rate notes	102		102		103
U.S. Treasury bonds and bills	225		225		250
Other	0		0		0
Derivative financial instruments	0		0		0
Total financial assets	9,294		9,294		24,888
Financial Liabilities [Abstract]
SERP liabilities	0		0		0
Total financial liabilities	0		0		0
Level 2 [Member]
Trading equity securities [Abstract]
SERP money market fund	0		0		0
SERP mutual funds	0		0		0
Preferred stocks	0		0		0
Short-term investments in mutual funds					0
Trading debt securities [Abstract]
Corporate bonds	1,134		1,134		1,155
Municipal bonds	1,901		1,901		1,908
Floating rate notes	324		324		446
U.S. Treasury bonds and bills	0		0		0
Other	1,107		1,107		864
Derivative financial instruments	460		460		452
Total financial assets	4,926		4,926		4,825
Financial Liabilities [Abstract]
SERP liabilities	7,922		7,922		7,828
Total financial liabilities	$ 7,922		$ 7,922		$ 7,828