Debt (Tables)

Sep. 30, 2011

Debt [Abstract]

Components of Debt Table

	September 30,		December 31,
	2011		2010
	(in thousands)
Short-term debt:
7.15% Senior Notes due 2018	$                1,200	$                1,200
Total short-term debt	1,200	1,200
Long-term debt:
Variable rate (2.205% at September 30, 2011 and 0.887% at December 31, 2010) unsecured revolving credit facility	599,800	421,200
7.5% Senior Notes due 2018	600,000	600,000
7.35% Senior Notes due 2017	15,000	15,000
7.125% Senior Notes due 2017	25,000	25,000
7.15% Senior Notes due 2018	31,200	31,800
	1,271,000	1,093,000
Total debt	$        1,272,200	$        1,094,200