CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
NET INCOME (LOSS)	$ (481)	$ (9,674)
Derivative instruments:
Net unrealized gain (loss), net of tax benefit (expense) of $16,551 and $(390)	(25,352)	598
Reclassification of net realized loss, net of tax benefit of $5,728 and $5,865	8,772	8,982
Pension and other postretirement benefits activity, net of tax expense of $631 and $566	966	866
Total other comprehensive income (loss)	(15,614)	10,446
COMPREHENSIVE INCOME (LOSS)	(16,095)	772
Less: Comprehensive income attributable to noncontrolling interests	7,776	5,461
COMPREHENSIVE LOSS ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ (23,871)	$ (4,689)