Changes in Accumulated Other Comprehensive (Loss) Earnings, Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (103,833)	$ (106,723)	$ (105,622)	$ (106,159)
Other comprehensive (loss) earnings before reclassifications, net of tax	(3,968)	(10,441)	(3,947)	(12,904)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	1,733	4,350	3,501	6,249
Other comprehensive (loss) earnings, net of tax	(2,235)	(6,091)	(446)	(6,655)
Balance at end of period	(106,068)	(112,814)	(106,068)	(112,814)
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(101,907)	(105,151)	(103,380)	(106,688)
Other comprehensive (loss) earnings before reclassifications, net of tax	(3,736)	(10,670)	(3,830)	(10,845)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	1,529	4,158	3,096	5,870
Other comprehensive (loss) earnings, net of tax	(2,207)	(6,512)	(734)	(4,975)
Balance at end of period	(104,114)	(111,663)	(104,114)	(111,663)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(149)	990	(264)	3,278
Other comprehensive (loss) earnings before reclassifications, net of tax	(232)	229	(117)	(2,059)
Other comprehensive (loss) earnings, net of tax	(232)	229	(117)	(2,059)
Balance at end of period	(381)	1,219	(381)	1,219
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,777)	(2,562)	(1,978)	(2,749)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	204	192	405	379
Other comprehensive (loss) earnings, net of tax	204	192	405	379
Balance at end of period	$ (1,573)	$ (2,370)	$ (1,573)	$ (2,370)