Stock-Based Compensation Plans - Activity Table (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Total Options and Non-Option Equity Instruments, Outstanding [Roll Forward]
Total outstanding, number	427,582
Total granted, number	177,768
Total exercised, number	(147,133)
Total canceled, number	(13,869)
Total outstanding, number	444,348
Total exercisable, number	158,944
2004 LTIP [Member] | Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, number	17,376
Granted, number	0
Exercised, number	(750)
Canceled, number	0
Outstanding, number	16,626
Exercisable, number	16,626
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 34.94
Granted, price	$ 0.00
Exercised, price	$ 36.03
Canceled, price	$ 0.00
Outstanding, price	$ 34.89
Exercisable, price	$ 34.89
2005 LTIP [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, number	3,053
Granted, number	0
Exercised, number	0
Canceled, number	0
Outstanding, number	3,053
Exercisable, number	3,053
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 0.01
Granted, price	$ 0.00
Exercised, price	$ 0.00
Canceled, price	$ 0.00
Outstanding, price	$ 0.01
Exercisable, price	$ 0.01
2007 LTIP [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, number	24,920
Granted, number	0
Exercised, number	(24,514)
Canceled, number	0
Outstanding, number	406
Exercisable, number	406
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 0.01
Granted, price	$ 0.00
Exercised, price	$ 0.01
Canceled, price	$ 0.00
Outstanding, price	$ 0.01
Exercisable, price	$ 0.01
2007 LTIP [Member] | Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, number	169,107
Granted, number	0
Exercised, number	(33,373)
Canceled, number	0
Outstanding, number	135,734
Exercisable, number	135,734
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 25.62
Granted, price	$ 0.00
Exercised, price	$ 24.40
Canceled, price	$ 0.00
Outstanding, price	$ 25.92
Exercisable, price	$ 25.92
2007 LTIP [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, number	8,453
Granted, number	0
Exercised, number	(8,453)
Canceled, number	0
Outstanding, number	0
Exercisable, number	0
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 0.01
Granted, price	$ 0.00
Exercised, price	$ 0.01
Canceled, price	$ 0.00
Outstanding, price	$ 0.00
Exercisable, price	$ 0.00
2010 LTIP [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, number	120,126
Granted, number	87,268	78,760
Exercised, number	(47,033)
Canceled, number	(667)
Outstanding, number	159,694
Exercisable, number	0
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 0.01
Granted, price	$ 0.01
Exercised, price	$ 0.01
Canceled, price	$ 0.01
Outstanding, price	$ 0.01
Exercisable, price	$ 0.00
2010 LTIP [Member] | Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, number	7,500
Granted, number	0
Exercised, number	0
Canceled, number	0
Outstanding, number	7,500
Exercisable, number	3,125
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 32.78
Granted, price	$ 0.00
Exercised, price	$ 0.00
Canceled, price	$ 0.00
Outstanding, price	$ 32.78
Exercisable, price	$ 32.78
2010 LTIP [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, number	77,047
Granted, number	90,500	81,375
Exercised, number	(33,010)
Canceled, number	(13,202)
Outstanding, number	121,335
Exercisable, number	0
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, price	$ 0.01
Granted, price	$ 0.01
Exercised, price	$ 0.01
Canceled, price	$ 0.01
Outstanding, price	$ 0.01
Exercisable, price	$ 0.00