Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended							1 Months Ended
	Mar. 19, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Common Stock	Mar. 31, 2013 Common Stock	Mar. 31, 2014 Restricted Stock Units	Mar. 31, 2013 Restricted Stock Units	Apr. 30, 2010 Caliburn Acquisition Contingent Convertible Preferred Stock	Apr. 30, 2013 Tranche One - Performance Stock Caliburn Acquisition Contingent Convertible Preferred Stock	Apr. 30, 2010 Tranche Two - Performance Stock Caliburn Acquisition Contingent Convertible Preferred Stock
Stockholders Equity Note [Line Items]
Dividends declared per common share (in USD per share)	$ 0.45	$ 0.45	$ 0.45
Dividend equivalents paid on outstanding restricted stock units		$ 1.6	$ 1.6
Restricted stock units vested and issued as common stock (shares)						822,312	482,711
Repurchased shares for award (shares)				323,190	177,969
Average repurchase price of shares for award (USD per share)				$ 52.06	$ 58.88
Repurchased common stock (shares)					169,809
Average repurchase price of common stock (in USD per share)					$ 58.93
Conversion to common stock shares if revenue targets are achieved (shares)								1,099,877		439,951
Conversion of Stock (shares)									659,926
Performance stock fair value at acquisition date								$ 32.5