Earnings Per Share - Number of Potential Common Shares that have been Excluded from Computation of Diluted Earnings Per Share for Indicated Period Due to Their Anti-Dilutive Nature (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Potential common shares	1,233	2,393	1,233	2,393