Shareholders' Equity - Summary of Outstanding Shares of Common Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Shares outstanding at beginning of year	43,420,000	43,054,000	43,130,000
Shares repurchased			(464,000)
Treasury shares issued for:
Restricted stock awards	108,000	206,000	162,000
401(k) plan		134,000	116,000
Employee stock options exercised	22,000	26,000	110,000
Shares outstanding at end of year	43,550,000	43,420,000	43,054,000