Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary of Significant Accounting Policies (Tables) [Abstract]

Accumulated other comprehensive loss

	December 31,
	2011			2010
Unrecognized actuarial loss and prior service costs	$	(46,482	)	$	(29,362	)
Cash flow hedges		(1,154	)		(1,122	)
Increase in estimated fair value of investment in debt securities		4,546			1,685
	$	(43,090	)	$	(28,799	)