Stockholder Equity - Additional information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholders Equity Note [Line Items]
Antidilutive securities excluded from determination of diluted earnings per common share	100,000	300,000	500,000
Share based compensation	$ 0	$ 0	$ 0
Restricted stock units granted	342,000	634,000
Restricted stock units forfeited	95,000	101,000
Outstanding restricted stock units	1,248,000	1,646,000	1,940,000
Outstanding exercisable stock options	31,500	51,000	101,000
Stock options granted	0	0	0
Stock options exercised	19,525	45,040	26,568
Stock options exercised, aggregate intrinsic value	1.1	1.7	0.9
Stock options outstanding, aggregate intrinsic value	2.4
Restricted Stock
Stockholders Equity Note [Line Items]
Share based compensation	23.0	23.4	25.1
Unrecognized compensation cost	$ 53.6	$ 50.4	$ 49.8
Restricted Stock | Maximum
Stockholders Equity Note [Line Items]
Restricted stock and restricted stock unit grants, vesting period	4 years
Restricted Stock Unit
Stockholders Equity Note [Line Items]
Restricted stock units granted	12,081	0	0
Restricted stock units forfeited	0
Weighted average remaining vesting period	3 years 2 months 1 day
Outstanding restricted stock units	12,081