Accumulated Other Comprehensive Income (Changes in AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 3,325
Other comprehensive income before reclassifications	596
Amounts reclassified from accumulated other comprehensive income	(18)
Other comprehensive income before reclassifications	578	362	315
Ending balance	3,903		3,325
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,003)
Other comprehensive income before reclassifications	52
Amounts reclassified from accumulated other comprehensive income	0
Other comprehensive income before reclassifications	52
Ending balance	(951)
Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	4,328
Other comprehensive income before reclassifications	544
Amounts reclassified from accumulated other comprehensive income	(18)
Other comprehensive income before reclassifications	526
Ending balance	$ 4,854