Basis Of Presentation (Effect On Park National Corporation's Capital Ratios) (Details)	Sep. 30, 2011
Tier 1 Leverage Ratio	9.67%
Tier 1 Risk-based Capital Ratio	13.96%
Total Risk-based Capital Ratio	16.44%
As Previously Reported [Member]
Tier 1 Leverage Ratio	9.73%
Tier 1 Risk-based Capital Ratio	14.04%
Total Risk-based Capital Ratio	16.52%
Effect Of Change [Member]
Tier 1 Leverage Ratio	(0.06%)
Tier 1 Risk-based Capital Ratio	(0.08%)
Total Risk-based Capital Ratio	(0.08%)