Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities
Total, cost	$ 37,329	$ 37,329	$ 41,605
Gross unrealized gains	9,692	9,692	7,536
Gross unrealized losses	(459)	(459)	(677)
Marketable equity securities, carrying value	39,500	39,500
Total available-for-sale investments, carrying value	46,562	46,562	48,464
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	4,966	4,966	5,961
Less than 12 months, gross unrealized loss	309	309	627
Greater than 12 months, fair value	1,609	1,609	2,249
Greater than 12 months, gross unrealized loss	150	150	50
Corporate Bonds
Schedule of Available-for-sale Securities
Fixed maturities, cost	6,837	6,837	7,758
Gross unrealized gains	240	240	324
Gross unrealized losses	(32)	(32)	(56)
Fixed maturities, carrying value	7,045	7,045	8,026
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	2,239	2,239	768
Less than 12 months, gross unrealized loss	32	32	12
Greater than 12 months, fair value			2,204
Greater than 12 months, gross unrealized loss			44
Marketable Equity Securities
Schedule of Available-for-sale Securities
Marketable equity securities, cost	30,492	30,492	33,847
Gross unrealized gains	9,452	9,452	7,212
Gross unrealized losses	(427)	(427)	(621)
Marketable equity securities, carrying value	39,517	39,517	40,438
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	2,727	2,727	5,193
Less than 12 months, gross unrealized loss	277	277	615
Greater than 12 months, fair value	1,609	1,609	45
Greater than 12 months, gross unrealized loss	150	150	6
Impairment losses, available-for-sale securities	$ 76	$ 998