Summary of Investments (Narratives) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Schedule of Investments [Line Items]
Trading securities	$ 12,441		$ 12,441		$ 15,371
Remaining potential off-balance sheet contractual obligation	1,950		1,950
Other-than-temporary impairment charges	(139)	0	(139)	(4)
Equity Securities [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Largest unrealized loss greater than 12 months on an individual security	$ 42		$ 42