Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income or Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance					$ (57,808)		$ (62,802)
Other comprehensive income before reclassifications					(6,133)		(4,674)
Pension and postretirement actuarial net gain (loss) incurred in fiscal year	17,225		0		17,225		0
Amounts reclassified from accumulated other comprehensive income					2,753		4,146
Net current-period other comprehensive income					13,845		(528)
Ending balance	(43,963)		(63,330)		(43,963)		(63,330)
AOCI, Pension and other postretirement benefit plans, tax	11,613		20,799		11,613		20,799		22,371	20,799
AOCI, Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Tax	87		23		87		23		127	0
AOCI, Available-for-sale Securities Adjustment, Tax										1,555
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance					12,585		5,875
Other comprehensive income before reclassifications					(6,206)		(4,886)
Pension and postretirement actuarial net gain (loss) incurred in fiscal year					0
Amounts reclassified from accumulated other comprehensive income					0		0
Net current-period other comprehensive income					(6,206)		(4,886)
Ending balance	6,379		989		6,379		989
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance					(70,158)	[1]	(67,239)	[2]
Other comprehensive income before reclassifications					0	[1]	0	[2]
Pension and postretirement actuarial net gain (loss) incurred in fiscal year					17,225
Amounts reclassified from accumulated other comprehensive income					2,753	[1]	2,978	[2]
Net current-period other comprehensive income					19,978	[1]	2,978	[2]
Ending balance	(50,180)	[1]	(64,261)	[2]	(50,180)	[1]	(64,261)	[2]
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance					(235)	[3]	(270)	[4]
Other comprehensive income before reclassifications					73	[3]	212	[4]
Pension and postretirement actuarial net gain (loss) incurred in fiscal year					0
Amounts reclassified from accumulated other comprehensive income					0	[3]	0	[4]
Net current-period other comprehensive income					73	[3]	212	[4]
Ending balance	(162)	[3]	(58)	[4]	(162)	[3]	(58)	[4]
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance							(1,168)	[5]
Other comprehensive income before reclassifications							0	[5]
Amounts reclassified from accumulated other comprehensive income							1,168	[5]
Net current-period other comprehensive income							1,168	[5]
Ending balance			$ 0	[5]			$ 0	[5]

[1] Net of taxes of $11,613 and $22,371 for the periods ended June 30, 2013 and December 31, 2012, respectively.

[2] Net of taxes of $20,799 and $20,799 for the periods ended June 30, 2012 and December 31, 2011, respectively.

[3] Net of taxes of $87 and $127 for the periods ended June 30, 2013 and December 31, 2012, respectively.

[4] Net of taxes of $23 and $0 for the periods ended June 30, 2012 and December 31, 2011, respectively.

[5] Net of taxes of $1,555 for the period ended December 31, 2011.