Earnings Per Share - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended				6 Months Ended	0 Months Ended	6 Months Ended	0 Months Ended			6 Months Ended	0 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	May 13, 2014	Feb. 25, 2014	Jun. 30, 2014 Common Stock	Feb. 03, 2014 Merrill Lynch Accelerated Share Repurchase Agreement tranche	Jun. 30, 2014 Merrill Lynch Accelerated Share Repurchase Agreement	Feb. 03, 2014 Merrill Lynch Accelerated Share Repurchase Agreement Initial Delivery	Feb. 03, 2014 Merrill Lynch Accelerated Share Repurchase Agreement Fair Market Value	Apr. 30, 2014 Merrill Lynch Accelerated Share Repurchase Agreement Final Settlement	Jun. 30, 2014 Merrill Lynch Accelerated Share Repurchase Agreement Total	Apr. 30, 2014 JP Morgan Accelerated Share Repurchase Agreement tranche	Apr. 30, 2014 JP Morgan Accelerated Share Repurchase Agreement Initial Delivery	Apr. 30, 2014 JP Morgan Accelerated Share Repurchase Agreement Fair Market Value	Jun. 30, 2014 JP Morgan Accelerated Share Repurchase Agreement Final Settlement	Jul. 14, 2014 Subsequent Event [Member]
Earnings Per Share Disclosure [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 82,472,000	$ 80,111,000	$ 140,824,000	$ 162,263,000
Increase in dividend rate, percentage						15.00%
Cash dividend, amount per share (in dollars per share)					$ 0.275	$ 0.275												$ 0.275
Stock Repurchase Program, Authorized Amount								50,000,000						100,000,000
Number of tranches								2						2
Authorized amount per tranche purchased								25,000,000						50,000,000
Payment for repurchase of common stock			150,000,000	582,298,000						50,000,000					100,000,000
Repurchase of common stock shares (in shares)										623,248		150,504	773,752		1,193,317		231,000
Share price minimum for repurchase agreement transaction (in dollars per share)														$ 33.50
Shares repurchased											$ 40,000,000					$ 80,000,000
Forward Purchase Price adjustment amount (in dollars per share)									$ 0.77
Shares repurchased (in shares)							1,967,069
Shares available for repurchase (in shares)	3,972,525		3,972,525