Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Capital Stock [Abstract]
Common stock, shares authorized (in shares)	100,000,000				100,000,000				100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.1				$ 0.1				$ 0.1	$ 0.1
Common stock, shares outstanding (in shares)	34,350,186				34,949,620				34,350,186	34,949,620
Preferred stock, authorized (in shares)	1,000,000				1,000,000				1,000,000	1,000,000
Preferred stock, issued (in shares)	0				0				0	0
Preferred stock, outstanding (in shares)	0								0
Stock split										Board of Directors authorized a two-for-one stock split of the of the Company's outstanding common stock
Conversion ratio (in hundredths)										100.00%
Increase in stock outstanding related to stock split (in shares)									17,600,000
Cash Dividends [Abstract]
Cash dividends paid									$ 6.9
Cash dividends paid (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.025	$ 0.025	$ 0.025	$ 0.20
Cash dividend declared	$ 1.7								$ 1.7
Cash dividend declared (in dollars per share)	$ 0.05								$ 0.05
Stock Award and Incentive Plan [Abstract]
Term of stock options granted under Plan									10 years
Vesting period, generally, for stock options granted under the plan									3 years
Shares available for grant [Roll Forward]
Balance, beginning of year (in shares)				1,491,974				1,677,738	1,491,974	1,677,738	1,898,578
Granted (in shares)									(351,995)	(345,696)	(381,624)
Exercised/vested (in shares)									0	0	0
Canceled (in shares)									5,010	159,932	160,784
Balance, end of year (in shares)	1,144,989				1,491,974				1,144,989	1,491,974	1,677,738
Stock Options [Member]
Stock options [Roll Forward]
Balance, beginning of year (in shares)				1,395,520				1,573,974	1,395,520	1,573,974	1,640,060
Granted (in shares)									239,770	222,250	244,646
Exercised (in shares)									(501,222)	(330,158)	(241,196)
Canceled (in shares)									(2,653)	(70,546)	(69,536)
Balance, end of year (in shares)	1,131,415				1,395,520				1,131,415	1,395,520	1,573,974
Weighted average exercise price per share, Stock options [Abstract]
Balance, beginning of year (in dollars per share)				$ 28.31				$ 27.10	$ 28.31	$ 27.10	$ 27.05
Granted (in dollars per share)									$ 41.42	$ 32.04	$ 32.06
Exercised (in dollars per share)									$ 25.26	$ 25.15	$ 25.01
Canceled (in dollars per share)									$ 37.24	$ 27.76	$ 26.80
Balance, end of year (in dollars per share)	$ 32.42				$ 28.31				$ 32.42	$ 28.31	$ 27.10
Restricted Stock [Member]
Restricted Stock [Roll Forward]
Balance, beginning of year (in shares)				183,660				252,024	183,660	252,024	300,540
Granted (in shares)									112,225	123,446	136,978
Exercised/vested (in shares)									(107,956)	(102,424)	(94,246)
Canceled (in shares)									(2,357)	(89,386)	(91,248)
Balance, end of year (in shares)	185,572				183,660				185,572	183,660	252,024
Weighted average grant date fair value per share, Restricted stock [Abstract]
Balance, beginning of year (in dollars per share)				$ 31.25				$ 27.21	$ 31.25	$ 27.21	$ 23.60
Granted (in dollars per share)									$ 41.44	$ 32.04	$ 32.08
Vested (in dollars per share)									$ 30.71	$ 25.90	$ 31.99
Canceled (in dollars per share)									$ 36.39	$ 27.08	$ 30.22
Balance, end of year (in dollars per share)	$ 37.65				$ 31.25				$ 37.65	$ 31.25	$ 27.21