Shareholders' Equity - Summary of Outstanding Shares of Common Stock (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Shares outstanding at beginning of year	44,248	43,959	43,614
Treasury shares issued for:
Restricted stock awards	110	188	304
Employee stock options exercised	10	101	41
Shares outstanding at end of year	44,368	44,248	43,959