Pension and Other Employee Benefits - Schedule Fair Value of Pension Plan Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total assets at fair value	$ 25,153	$ 25,662
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total fixed income	13,110	24,263
U.S. government [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total fixed income	3,849	4,384
Investment grade [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total fixed income	6,239	16,916
Investment grade [Member] | Level 2 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total assets at fair value	11,560
High yield [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total fixed income	3,022	2,963
Other [Member] | Level 2 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total assets at fair value	222	260
Cash and cash equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Total assets at fair value	$ 261	$ 1,139