Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 65,523	$ 67,552	$ 66,467	$ 68,568
Other comprehensive earnings, tax effect, Pension and Postretirement Benefit Plans	1,408	4,073	464	3,057
Balance at end of period, Pension and Postretirement Benefit Plans	66,931	71,625	66,931	71,625
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,159	1,679	1,290	1,799
Other comprehensive earnings, tax effect, Unamortized Value of Terminated Forward Starting Interest Rate Swap	(136)	(125)	(267)	(245)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,023	1,554	1,023	1,554
Balance at beginning of period, Net Non current Deferred Tax Assets	66,682	69,231	67,757	70,367
Other comprehensive earnings, tax effect, Net Non current Deferred Tax Assets	1,272	3,948	197	2,812
Balance at end of period, Net Non current Deferred Tax Assets	$ 67,954	$ 73,179	$ 67,954	$ 73,179