Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended	116 Months Ended
	Mar. 31, 2017 USD ($) shares	Mar. 31, 2017 USD ($) $ / shares shares
Schedule of Trading Securities and Other Trading Assets [Line Items]
Treasury stock, total repurchase during period (in shares)		10,488,000
Treasury stock, average price of share repurchased (in dollars per share) | $ / shares		$ 27.83
Treasury stock, total cost of repurchased stock | $		$ 291.8
Stock repurchase program, remaining amount available for repurchase | $	$ 158.2	$ 158.2
Performance Shares | Minimum
Schedule of Trading Securities and Other Trading Assets [Line Items]
Performance awards, percentage of grant available to vest	0.00%
Performance Shares | Maximum
Schedule of Trading Securities and Other Trading Assets [Line Items]
Performance awards, percentage of grant available to vest	100.00%
Employee Stock Purchase Plan
Schedule of Trading Securities and Other Trading Assets [Line Items]
Shares reserved for grant	363,002	363,002
2003 Plan | Employee Stock Option
Schedule of Trading Securities and Other Trading Assets [Line Items]
Shares reserved for grant	2,200,000	2,200,000