Investments (Details 4) (Donegal Financial Services Corporation [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Donegal Financial Services Corporation [Member]
Balance sheets:
Total assets	$ 514,200		$ 509,670
Total liabilities	436,590		433,490
Stockholders' equity	77,610		76,180
Total liabilities and stockholders' equity	514,200		509,670
Income statements:
Net income	$ 2,258	$ 2,436