Benefit Plans - Components of Accumulated Other Comprehensive Loss (Gain) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	$ 0	$ 0
Unrecognized net actuarial loss (gain)	12,155	10,887
Total accumulated other comprehensive loss (gain)	12,155	10,887
Post-retirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	0	(1)
Unrecognized net actuarial loss (gain)	(1,498)	1,788
Total accumulated other comprehensive loss (gain)	$ (1,498)	$ 1,787