Changes in Accumulated Other Comprehensive Earnings, Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (112,814)	$ (42,141)	$ (106,159)	$ (44,114)
Other comprehensive (loss) earnings before reclassifications, net of tax	(1,757)	(1,466)	(14,661)	(141)
Amounts reclassified from accumulated other comprehensive loss, net of tax	1,829	326	8,078	974
Other comprehensive earnings (loss), net of tax	72	(1,140)	(6,583)	833
Balance at end of period	(112,742)	(43,281)	(112,742)	(43,281)
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(111,663)	(44,685)	(106,688)	(44,549)
Other comprehensive (loss) earnings before reclassifications, net of tax			(10,845)	(431)
Amounts reclassified from accumulated other comprehensive loss, net of tax	1,636	146	7,506	441
Other comprehensive earnings (loss), net of tax	1,636	146	(3,339)	10
Balance at end of period	(110,027)	(44,539)	(110,027)	(44,539)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1,219	5,658	3,278	3,902
Other comprehensive (loss) earnings before reclassifications, net of tax	(1,757)	(1,466)	(3,816)	290
Other comprehensive earnings (loss), net of tax	(1,757)	(1,466)	(3,816)	290
Balance at end of period	(538)	4,192	(538)	4,192
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2,370)	(3,114)	(2,749)	(3,467)
Amounts reclassified from accumulated other comprehensive loss, net of tax	193	180	572	533
Other comprehensive earnings (loss), net of tax	193	180	572	533
Balance at end of period	$ (2,177)	$ (2,934)	$ (2,177)	$ (2,934)