Accumulated other comprehensive income (loss): (Tables)

3 Months Ended

Mar. 31, 2013

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income Comprises Changes in Equity

Accumulated other comprehensive income (loss) comprises changes in equity as presented in the table below. See Note 7 for amounts related to our defined benefit pension plans and OPEB plans.

	Three months ended
	March 31,
	2012			2013
	(In thousands)
Accumulated other comprehensive income (loss), net of tax:
Defined benefit pension plans:
Balance at beginning of year	$	(192,552	)	$	(179,731	)
Other comprehensive income:
Amortization of prior service cost		186			186
Amortization of net actuarial losses		2,682			2,495
Balance at March 31	$	(189,684	)	$	(177,050	)
Defined benefit OPEB plans:
Balance at beginning of year	$	10,459		$	2,689
Other comprehensive income (loss):
Amortization of prior service credit		(2,442	)		(2,442	)
Amortization of net actuarial losses		1,159			1,128
Balance at March 31	$	9,176		$	1,375
Total accumulated other comprehensive income (loss):
Balance at beginning of year	$	(182,093	)	$	(177,042	)
Other comprehensive income		1,585			1,367
Balance at March 31	$	(180,508	)	$	(175,675	)