Shareholders' Investment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Change in total shareholders' investment
Beginning Balance			$ 220,629	$ 196,537
Net income	1,160	7,411	5,710	13,732
Stock options exercised			60	40
Options granted			199	208
Employee Stock Purchase Plan			839	888
Stock appreciation rights				88
Amortization of restricted stock			1,376	1,509
Treasury share purchases			(272)	(86)
Profit distribution			(555)	(865)
Other comprehensive (loss)/income, net of tax:
Unrealized (loss)/gain on investments, net of reclassification adjustments		(47)	47	(30)
Foreign currency translation adjustments			43	20
Ending Balance	228,076	212,041	228,076	212,041
Total Michael Baker Corporation Shareholders' Investment [Member]
Change in total shareholders' investment
Beginning Balance			219,912	195,815
Net income			5,125	12,918
Stock options exercised			60	40
Options granted			199	208
Employee Stock Purchase Plan			839	888
Stock appreciation rights				88
Amortization of restricted stock			1,376	1,509
Treasury share purchases			(272)	(86)
Other comprehensive (loss)/income, net of tax:
Unrealized (loss)/gain on investments, net of reclassification adjustments			47	(30)
Foreign currency translation adjustments			43
Ending Balance	227,329	211,370	227,329	211,370
Non-controlling Interests [Member]
Change in total shareholders' investment
Beginning Balance			717	722
Net income			585	814
Profit distribution			(555)	(865)
Other comprehensive (loss)/income, net of tax:
Ending Balance	$ 747	$ 671	$ 747	$ 671