Cash Value of Life Insurance (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Policy Company Employee	Mar. 31, 2012 Company Employee Policy
Summary of the activity in the balance of cash value of life insurance
Beginning balance	$ 50,582	$ 50,403
Increase in cash value of life insurance	426	450
Ending balance	51,008	50,853
End of period death benefit	$ 94,234	$ 95,593
Number of policies owned	133	139
Insurance companies used	6	6
Current and former employees and directors covered	36	38