Consolidated Statements of Changes in Stockholders' Equity (Deficit) (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Accumulated Other Comprehensive Loss	Additional Paid-In Capital	Treasury Stock, at Cost	Accumulated Deficit
Balance at Dec. 31, 2010	$ (30,160)	$ 122	$ (135,865)	$ 552,844		$ (447,261)
Balance (in shares) at Dec. 31, 2010		12,179
Stockholders' Equity Line Items
Amortization, issuance, and forfeitures of restricted stock grants (in shares)		467
Amortization, issuance and forfeitures of restricted stock grants	2,907	5		2,902		0
Unrealized gain (loss) on available-for-sale investments, net of tax	4,821		4,821
Changes in pension liability and post-retirement benefit obligations, net of tax	(55,594)		(55,594)
Foreign currency translation adjustments	(1,751)		(1,751)
Net income	138,775					138,775
Balance at Dec. 31, 2011	58,998	127	(188,389)	555,746		(308,486)
Balance (in shares) at Dec. 31, 2011		12,646
Stockholders' Equity Line Items
Amortization, issuance, and forfeitures of restricted stock grants (in shares)		494
Amortization, issuance and forfeitures of restricted stock grants	4,228	4		4,224		0
Unrealized gain (loss) on available-for-sale investments, net of tax	(8,894)		(8,894)
Changes in pension liability and post-retirement benefit obligations, net of tax	(29,247)		(29,247)
Foreign currency translation adjustments	362		362
Net income	26,481					26,481
Balance at Dec. 31, 2012	51,928	131	(226,168)	559,970		(282,005)
Balance (in shares) at Dec. 31, 2012		13,140
Stockholders' Equity Line Items
Amortization, issuance, and forfeitures of restricted stock grants (in shares)		304
Amortization, issuance and forfeitures of restricted stock grants	5,474	3		5,471		0
Unrealized gain (loss) on available-for-sale investments, net of tax	1,710		1,710
Reclassification of unrealized loss on available-for-sale investments, net of tax	2,362		2,362
Changes in pension liability and post-retirement benefit obligations, net of tax	42,675		42,675
Foreign currency translation adjustments	(2,510)		(2,510)
Purchases of treasury stock	(9,796)				(9,796)
Net income	42,029					42,029
Balance at Dec. 31, 2013	$ 133,872	$ 134	$ (181,931)	$ 565,441	$ (9,796)	$ (239,976)
Balance (in shares) at Dec. 31, 2013		13,444