Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								3 Months Ended								3 Months Ended				6 Months Ended				3 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012		Dec. 31, 2011		Jun. 30, 2013 Gains/(Losses) on Cash Flow Hedges [Member]		Jun. 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]		Jun. 30, 2013 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Jun. 30, 2012 Unrealized Gains and Losses on Available-for-Sale Securities [Member]		Jun. 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]		Jun. 30, 2013 Supplemental Executive Retirement Plans [Member]		Jun. 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	(594)	[1]	(296)	[1]					166	[1]	(368)	[1]					(760)	[1]	72	[1]					0	[1]	0	[1]
Amounts reclassified from accumulated other comprehensive income	0	[1]	(108)	[1]					0	[1]	0	[1]					0	[1]			(108)	[1]			0	[1]	0	[1]
Net current-period other comprehensive income	(594)	[1]	(404)	[1]					166	[1]	(368)	[1]					(760)	[1]	(36)	[1]					0	[1]	0	[1]
Ending balance	$ (2,306)	[1]	$ (1,721)	[1]	$ (1,712)	[1]	$ (1,317)	[1]	$ (195)	[1]	$ (548)	[1]	$ (361)	[1]	$ (180)	[1]	$ (2,158)	[1]	$ (1,412)	[1]	$ (1,412)	[1]	$ (1,398)	[1]	$ 47	[1]	$ 239	[1]	$ 47	[1]	$ 239	[1]

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