Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 68,568	$ 29,198
Other comprehensive earnings, tax effect, Pension and Postretirement Benefit Plans	(1,016)	(182)
Balance at end of period, Pension and Postretirement Benefit Plans	67,552	29,016
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,799	2,269
Other comprehensive earnings, tax effect, Unamortized Value of Terminated Forward Starting Interest Rate Swap	(120)	(114)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,679	2,155
Balance at beginning of period, Net Non current Deferred Tax Assets	70,367	31,467
Other comprehensive earnings, tax effect, Net Non current Deferred Tax Assets	(1,136)	(296)
Balance at end of period, Net Non current Deferred Tax Assets	$ 69,231	$ 31,171