Cost and Fair Value Basis of Long-Term Debt (tables)

9 Months Ended

Sep. 30, 2011

Long-term Debt Current And Noncurrent Abstract

Fair Value Of Long Term Debt Table [Text Block]

	September 30,					December 31,
Thousands		2011		2010		2010
Carrying amount	$	641,700	$	636,700	$	601,700
Estimated fair value	$	774,186	$	740,731	$	690,126