Credit Facilities (Tabels)

12 Months Ended

Dec. 31, 2011

Credit Facilities [Abstract]

Outstanding amount of credit facilities

	December 31
	2011		2010
	(In thousands)
Unsecured term notes:
November 30, 2001, Series B Senior Notes, $250,000,000, 6.23% fixed, due November 30, 2011	$	—	$	250,000
November 30, 2008, Series C Senior Unsecured Notes, $250,000,000, 4.67% fixed, due November 30, 2013		250,000		250,000
November 30, 2011, Series D and E Senior Unsecured Notes, $250,000,000, 3.35% fixed, due November 30, 2016		250,000		—
Total debt		500,000		500,000
Less debt due within one year		—		250,000
Long-term debt, excluding current portion	$	500,000	$	250,000