CAPITAL CONSTRUCTION FUND (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
CAPITAL CONSTRUCTION FUND
Maximum period to commit fund deposits for qualified purposes	25 years
Period over which deposits will be treated as non-qualified withdrawals	5 years
Accrued withdrawal from the CCF	$ 4.4	$ 4.4
Accrued deposits to the CCF	4.4	4.4
Net balance of amounts accrued for CCF	$ 0	$ 0