Stock-Based Awards and Programs (Details) (USD $)	3 Months Ended		12 Months Ended		3 Months Ended									12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Performance-Based Restricted Stock Awards Y	Mar. 31, 2011 Performance-Based Restricted Stock Awards Y	Mar. 31, 2012 Performance-Based Restricted Stock Awards Minimum	Mar. 31, 2011 Performance-Based Restricted Stock Awards Minimum	Mar. 31, 2012 Performance-Based Restricted Stock Awards Maximum	Mar. 31, 2011 Performance-Based Restricted Stock Awards Maximum	Mar. 31, 2012 Stock Options M	Mar. 31, 2011 Stock Options M	Mar. 31, 2012 Time-Vested Restricted Stock Awards	Dec. 31, 2011 Time-Vested Restricted Stock Awards M	Mar. 31, 2011 Time-Vested Restricted Stock Awards
Stock-Based Awards and Programs
Compensation expense	$ 822,000	$ 741,000	$ 1,846,000	$ 3,136,000
Tax benefit recognized	298,000	271,000	642,000	1,143,000
Assumptions used in the model for each grant year
Risk-free interest rate, low end of range (as a percent)					0.16%	0.61%					0.17%	0.45%
Risk-free interest rate, high end of range (as a percent)					0.45%	1.15%					0.83%	2.39%
Expected volatility (as a percent)					21.50%	26.10%					25.00%	23.00%
Expected volatility of peer group stock (as a percent)							13.50%	21.10%	51.90%	82.20%
Expected dividend yield on Empire stock (as a percent)					4.90%	6.30%					4.90%	6.30%
Expected forfeiture rates (as a percent)					3.00%	3.00%
Plan cycle (in years)					3	3
Fair value percentage							41.00%	97.00%	104.00%	143.00%
Expected life (in months)											78	78
Weighted average fair value per share (in dollars per share)					$ 13.63	$ 27.20
Market value (in dollars per share)											$ 20.35	$ 21.79
Weighted average fair value per option (in dollars per share)											$ 1.56	$ 1.94
Changes in restricted stock awards
Nonvested, balance at the beginning of the period (in shares)					37,400	47,500							3,433
Granted (in shares)					10,000	10,900								10,200
Awarded (in shares)					(7,823)	(39,621)								(794)
Awarded in excess of target (in shares)						18,621
Not Awarded (in shares)					(5,677)
Distributed (in shares)													133	661
Forfeited (in shares)														6,106
Vested but not distributed (in shares)														133
Nonvested, balance at the end of the period (in shares)					33,900	37,400							3,300	3,433
Weighted Average Grant Date Price
Nonvested, balance at the beginning of the period (in dollars per share)					$ 19.28	$ 19.86							$ 21.84		$ 21.84
Granted (in dollars per share)					$ 20.97	$ 21.84								$ 21.84
Awarded (in dollars per share)					$ 18.12	$ 21.92								$ 19.32
Awarded in Excess of Target (in dollars per share)						$ 21.92
Not Awarded (in dollars per share)					$ 18.12
Distributed/Awarded (in dollars per share)													$ 20.13	$ 21.02
Vested but not distributed (in dollars per share)														$ 20.13
Nonvested, balance at the end of the period (in dollars per share)					$ 20.25	$ 19.28							$ 20.35	$ 21.84	$ 21.84
Unrecognized compensation cost related to estimated outstanding awards					$ 200,000
Period from date of termination of employment due to death, retirement or disability during which the pro-rata portion of the awards are distributed (in months)														6
Vesting period (in years)														3 years