Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 9,150		$ 9,150		$ 9,150
Net Unrealized Gain (Loss)	650		650		50
Changes in fair value of investments [Roll Forward]
Change in net unrealized gain (loss)	300	500	600	800
Fair value at beginning of period	9,500	8,800	9,200	8,500
Fair value at end of period	9,800	9,300	9,800	9,300
Minimum [Member]
Changes in fair value of investments [Roll Forward]
Fair Value Inputs Discount Rate	1.40%
Fair Value Input, Interest Rate Premium	4.00%
Time horizon present value calculations	3
Maximum [Member]
Changes in fair value of investments [Roll Forward]
Fair Value Inputs Discount Rate	2.50%
Fair Value Input, Interest Rate Premium	12.00%
Time horizon present value calculations	8
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)	50		50		(250)
Changes in fair value of investments [Roll Forward]
Change in net unrealized gain (loss)	300	600	300	600
Fair value at beginning of period	6,900	6,100	6,900	6,100
Fair value at end of period	7,200	6,700	7,200	6,700
Contractual maturities for debt securities, low range (in years)	12		12
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)	600		600		300
Changes in fair value of investments [Roll Forward]
Change in net unrealized gain (loss)	0	(100)	300	200
Fair value at beginning of period	2,600	2,700	2,300	2,400
Fair value at end of period	2,600	2,600	2,600	2,600
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