Investments (Mortgage Loans and Real Estate) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended			12 Months Ended		3 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012	Dec. 31, 2012		Sep. 30, 2012 Other Long-term Investments [Member]	Jun. 30, 2013 Less than 50% [Member]	Dec. 31, 2012 Less than 50% [Member]	Jun. 30, 2013 50% to 60% [Member]	Dec. 31, 2012 50% to 60% [Member]	Jun. 30, 2013 60% to 70% [Member]	Dec. 31, 2012 60% to 70% [Member]	Jun. 30, 2013 70% to 80% [Member]	Dec. 31, 2012 70% to 80% [Member]	Jun. 30, 2013 80% to 90% [Member]	Dec. 31, 2012 80% to 90% [Member]	Jun. 30, 2013 Greater than 90% [Member]	Dec. 31, 2012 Greater than 90% [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan, amount	$ 120,022			$ 120,022			$ 142,820			$ 46,364	$ 58,754	$ 20,856	$ 27,832	$ 21,163	$ 23,518	$ 8,600	$ 9,431	$ 0	$ 0	$ 23,039	$ 23,285
Allowance for possible losses, amount	(650)			(650)			(650)
Totals, amount	119,372	[1]		119,372	[1]		142,170	[1]
Mortgage loans, percentage	100.00%			100.00%			100.00%			38.60%	41.10%	17.40%	19.50%	17.60%	16.50%	7.20%	6.60%	0.00%	0.00%	19.20%	16.30%
Allowance for possible losses, percentage	(0.50%)			(0.50%)			(0.50%)
Totals, percentage	99.50%	[1]		99.50%	[1]		99.50%	[1]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period				650		4,571	4,571
Provision				0			650
Releases				0			(4,571)
Balance, end of period	650		650	650		650	650
Net gain on sale of real estate investment	$ 0		$ 159	$ 0		$ 159			$ 2,700

[1] Loan-to-Value Ratio using the most recent appraised value.