Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ (26,692)	$ (22,268)
Unrealized gains (losses) arising during period	0	0
Amounts reclassified from accumulated other comprehensive loss	74	11
Income tax benefit	4
Net other comprehensive income (loss)	78	11
Balance	(26,614)	(22,257)
Minimum Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(20,149)	(22,268)
Unrealized gains (losses) arising during period	0	0
Amounts reclassified from accumulated other comprehensive loss	(9)	11
Income tax benefit	4
Net other comprehensive income (loss)	(5)	11
Balance	(20,154)	(22,257)
Other-Than-Temporary Impairment of Investment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(6,543)
Unrealized gains (losses) arising during period	0	$ 0
Amounts reclassified from accumulated other comprehensive loss	83
Net other comprehensive income (loss)	83
Balance	$ (6,460)