Stockholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 22, 2019	Dec. 31, 2015
Stockholders Equity [Line Items]
Common stock, shares issued	93,400,929	92,637,403
Treasury stock, shares	10,174,589	6,519,773
Share Repurchase Program, authorized amount	$ 250,000,000
Shares repurchased	3,654,816
Stock repurchased during period, total cost	$ 98,032,000
Treasury stock at cost	252,903,000	$ 154,871,000
Dividends payable	84,000	470,000
Dividends paid to stockholders	$ 325,000	$ 1,544,000	$ 65,306,000
Share Repurchase Program [Member]
Stockholders Equity [Line Items]
Shares repurchased	3,654,816
Stock repurchased during period, total cost	$ 98,000,000
Share Repurchase Program, remaining authorized repurchase amount	$ 92,000,000
Stock Repurchase Program, number of shares repurchased		0	0
Share Repurchase Program [Member] | Subsequent Event [Member]
Stockholders Equity [Line Items]
Share Repurchase Program, authorized amount				$ 250,000,000
Stock Repurchase Program, replenishment amount				$ 158,000,000
Common Stock [Member]
Stockholders Equity [Line Items]
Common stock, shares issued	93,400,929	92,637,403	91,861,054		90,320,374
Number of unvested shares	920,904
Restricted Stock Units [Member]
Stockholders Equity [Line Items]
Number of unvested shares	1,696,996