Accumulated Other Comprehensive Income (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
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning balance			$ 19,571
Other comprehensive income (loss) before reclassifications			(10,907)
Amounts reclassified from accumulated other comprehensive income			(5,470)
Total other comprehensive income (loss), net of tax	(4,027)	4,387	(16,377)	7,893
Ending balance	3,194		3,194
Unrealized Gains on Available-for-Sale Securities [Member]
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning balance			19,663
Other comprehensive income (loss) before reclassifications			(10,999)
Amounts reclassified from accumulated other comprehensive income			(5,470)
Total other comprehensive income (loss), net of tax			(16,469)
Ending balance	3,194		3,194
Derivative Financial Instrument [Member]
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning balance			(92)
Other comprehensive income (loss) before reclassifications			92
Amounts reclassified from accumulated other comprehensive income			0
Total other comprehensive income (loss), net of tax			92
Ending balance	$ 0		$ 0