Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Investments [Abstract]
Contractual maturities for debt securities, low range (in years)			13Y
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 9,150		$ 9,150		$ 9,150
Net Unrealized Gain (Loss)	250		250		(650)
Changes in fair value of investments [Roll Forward]
Fair value at beginning of period	9,300	9,700	8,500	8,600
Temporary impairment credits, net	100	0	900	1,100
Fair value at end of period	9,400	9,700	9,400	9,700
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	7,150		7,150		7,150
Net Unrealized Gain (Loss)	(450)		(450)		(1,050)
Changes in fair value of investments [Roll Forward]
Fair value at beginning of period	6,700	6,900	6,100	6,700
Temporary impairment credits, net	0	300	600	500
Fair value at end of period	6,700	7,200	6,700	7,200
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,000		2,000		2,000
Net Unrealized Gain (Loss)	700		700		400
Changes in fair value of investments [Roll Forward]
Fair value at beginning of period	2,600	2,800	2,400	1,900
Temporary impairment credits, net	100	(300)	300	600
Fair value at end of period	2,700	2,500	2,700	2,500
Preferred Stock Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	0		0		0
Changes in fair value of investments [Roll Forward]
Fair value at beginning of period					0
Fair value at end of period	$ 0		$ 0		$ 0