COMMON STOCK (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 17, 2012	Sep. 17, 2012	Jun. 15, 2012	Mar. 15, 2012
Dividends
Expected dividend payable per share after suspension period (in dollars per share)				$ 0.25	$ 0.25	$ 0.25	$ 0.25
Period of suspension of dividend	6 months
First quarterly dividend paid excluded from EDE Mortgage covenant	$ 98,000
Cumulative aggregate amount up to which the entity may declare or pay any dividends as per EDE Mortgage covenant	10,750,000
Maximum period for payment of dividend after the related date of declaration or notice of dividend as per EDE Mortgage covenant	60 days
Ratio of total indebtedness to total capitalization	0.625
Retained earnings balance	47,115,000	33,707,000
Dividends paid	$ 42,273,000	$ 26,732,000	$ 51,996,000
401 (k) plan and ESOP
401 (k) plan and ESOP
Maximum percentage of annual compensation to be deferred by participating employees	25.00%
Percentage of each employee's deferrals to be matched	50.00%
Maximum matching contribution as a percentage of employee's eligible compensation	3.00%
Shares available to be issued	320,576	36,038
Shares contributed	65,502	68,523	64,830