Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Comprehensive Income (Loss)
Net income (loss)	$ (8,173)	$ 8,863	$ 6,804	$ (94,049)	$ (83,353)
Other comprehensive income (loss):
Adjustment to pension liability	1,672	1,501	5,015	4,503
Tax expense	(669)	(601)	(2,006)	(1,801)
Adjustment to pension liability, net of tax	1,003	900	3,009	2,702
Foreign currency translation adjustments	1,056	871	(663)	842
Total other comprehensive income, net of tax	2,059	1,771	2,346	3,544
Comprehensive income (loss)	(6,114)	10,634	9,150	(90,505)
Accumulated other comprehensive income (loss)
Balance at beginning of period			(49,734)	(45,323)	(45,323)
Other comprehensive loss, net of tax, before reclassifications			(663)	(842)
Amounts reclassified from accumulated other comprehensive income, net of tax			3,009	2,702
Net current period other comprehensive income (loss), net of tax			2,346	1,860	(4,411)
Balance at end of period	(47,388)	43,463	(47,388)	43,463	(49,734)
Defined Benefit Pension Items
Accumulated other comprehensive income (loss)
Balance at beginning of period			(54,431)	(48,705)	(48,705)
Other comprehensive loss, net of tax, before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive income, net of tax			3,009	2,702
Net current period other comprehensive income (loss), net of tax			3,009	2,702
Balance at end of period	(51,422)	(46,003)	(51,422)	(46,003)
Foreign Currency Items
Accumulated other comprehensive income (loss)
Balance at beginning of period			4,697	3,382	3,382
Other comprehensive loss, net of tax, before reclassifications			(663)	(842)
Amounts reclassified from accumulated other comprehensive income, net of tax			0	0
Net current period other comprehensive income (loss), net of tax			(663)	(842)
Balance at end of period	$ 4,034	$ 2,540	$ 4,034	$ 2,540