Changes in Accumulated Other Comprehensive Earnings, Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (106,723)	$ (42,744)	$ (106,159)	$ (44,114)
Other comprehensive (loss) earnings before reclassifications, net of tax	(10,441)	416	(12,904)	1,326
Amounts reclassified from accumulated other comprehensive loss, net of tax	4,350	187	6,249	647
Other comprehensive (loss) earnings, net of tax	(6,091)	603	(6,655)	1,973
Balance at end of period	(112,814)	(42,141)	(112,814)	(42,141)
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(105,151)	(44,267)	(106,688)	(44,549)
Other comprehensive (loss) earnings before reclassifications, net of tax	(10,670)	(426)	(10,845)	(430)
Amounts reclassified from accumulated other comprehensive loss, net of tax	4,158	8	5,870	294
Other comprehensive (loss) earnings, net of tax	(6,512)	(418)	(4,975)	(136)
Balance at end of period	(111,663)	(44,685)	(111,663)	(44,685)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	990	4,816	3,278	3,902
Other comprehensive (loss) earnings before reclassifications, net of tax	229	842	(2,059)	1,756
Other comprehensive (loss) earnings, net of tax	229	842	(2,059)	1,756
Balance at end of period	1,219	5,658	1,219	5,658
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2,562)	(3,293)	(2,749)	(3,467)
Amounts reclassified from accumulated other comprehensive loss, net of tax	192	179	379	353
Other comprehensive (loss) earnings, net of tax	192	179	379	353
Balance at end of period	$ (2,370)	$ (3,114)	$ (2,370)	$ (3,114)