Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								3 Months Ended								3 Months Ended				9 Months Ended				3 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012		Dec. 31, 2011		Sep. 30, 2013 Gains/(Losses) on Cash Flow Hedges [Member]		Sep. 30, 2012 Gains/(Losses) on Cash Flow Hedges [Member]		Dec. 31, 2012 Gains/(Losses) on Cash Flow Hedges [Member]		Dec. 31, 2011 Gains/(Losses) on Cash Flow Hedges [Member]		Sep. 30, 2013 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Sep. 30, 2012 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Sep. 30, 2012 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Dec. 31, 2012 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Sep. 30, 2013 Supplemental Executive Retirement Plans [Member]		Sep. 30, 2012 Supplemental Executive Retirement Plans [Member]		Dec. 31, 2012 Supplemental Executive Retirement Plans [Member]		Dec. 31, 2011 Supplemental Executive Retirement Plans [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance					$ (1,712)	[1]	$ (1,317)	[1]					$ (361)	[1]	$ (180)	[1]					$ (1,376)	[1]	$ (1,398)	[1]					$ 47	[1]	$ 239	[1]
Other comprehensive income (loss) before reclassifications	(566)	[1]	(175)	[1]					166	[1]	(419)	[1]					(732)	[1]	244	[1]					0	[1]	0	[1]
Amounts reclassified from accumulated other comprehensive income	0	[1]	(109)	[1]					0	[1]	0	[1]					0	[1]			(109)	[1]			0	[1]	0	[1]
Net current-period other comprehensive income	(566)	[1]	(284)	[1]					166	[1]	(419)	[1]					(732)	[1]	135	[1]					0	[1]	0	[1]
Ending balance	$ (2,278)	[1]	$ (1,601)	[1]	$ (1,712)	[1]	$ (1,317)	[1]	$ (195)	[1]	$ (599)	[1]	$ (361)	[1]	$ (180)	[1]	$ (2,130)	[1]	$ (1,241)	[1]	$ (1,241)	[1]	$ (1,398)	[1]	$ 47	[1]	$ 239	[1]	$ 47	[1]	$ 239	[1]

[1] All amounts are net of tax. Amounts in parentheses indicate debits.