Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.8.0.1
Fair Value Measurements - Additional Information (Detail)
Dec. 31, 2017
USD ($)
Fair Value Disclosures [Abstract]  
Fair value, assets, level 1 to level 2 transfers, amount $ 0
Fair value, assets, level 2 to level 1 transfers, amount $ 0