Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 66,931	$ 71,625	$ 66,467	$ 68,568
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans	(986)	(1,042)	(522)	2,015
Balance at end of period, Pension and Postretirement Benefit Plans	65,945	70,583	65,945	70,583
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,023	1,554	1,290	1,799
Tax effect of other comprehensive earnings, Unamortized Value of Terminated Forward Starting Interest Rate Swap	(136)	(125)	(403)	(370)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	887	1,429	887	1,429
Balance at beginning of period, Net Noncurrent Deferred Tax Assets	67,954	73,179	67,757	70,367
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets	(1,122)	(1,167)	(925)	1,645
Balance at end of period, Net Noncurrent Deferred Tax Assets	$ 66,832	$ 72,012	$ 66,832	$ 72,012