Goodwill and Other Intangible Assets - Intangible Assets- Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Net Carrying Amount	$ 2,216	$ 2,158
Intangible asset amortization expense, excluding impairment charge	1,500	$ 4,400	$ 7,100
Estimated Intangible asset amortization expense 2019	846
Estimated Intangible asset amortization expense 2020	529
Estimated Intangible asset amortization expense 2021	356
Estimated Intangible asset amortization expense 2022	241
Estimated Intangible asset amortization expense 2023	147
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	$ 97