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Significant Accounting Policies - Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Equity [Abstract] |  |  |  |
Balance at beginning of period, Net Noncurrent Deferred Tax Assets | $ 83,339 | $ 79,321 | $ 84,207 | $ 80,116
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets | (922) | (702) | (1,790) | (1,497)
Balance at end of period, Net Noncurrent Deferred Tax Assets | 82,417 | 78,619 | 82,417 | 78,619
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets | 922 | 702 | 1,790 | 1,497
Balance at beginning of period, Pension and Postretirement Benefit Plans | 83,339 | 79,280 | 84,207 | 79,938
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans | (922) | (661) | (1,790) | (1,319)
Balance at end of period, Pension and Postretirement Benefit Plans | $ 82,417 | 78,619 | $ 82,417 | 78,619
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap |  | 41 |  | 178
Tax effect of other comprehensive earnings, Unamortized Value of Terminated Forward Starting Interest Rate Swap |  | $ (41) |  | $ (178)

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