Share-Based Compensation - Summary of Stock Option Activity (Details) (USD $)	3 Months Ended
	Mar. 31, 2014
Summary of stock option activity
Options outstanding, Beginning Balance, Shares	314,323
Options outstanding, Beginning Balance, Weighted Average Exercise Price	$ 19.79
Options outstanding, Beginning Balance, Options Exercisable	314,323
Exercised, Shares	(36,815)
Exercised, Weighted Average Exercise Price	$ 19.26
Shares Forfeited or Expired	(18,522)
Weighted Average Exercise Price Forfeited	$ 35.28
Additional Shares Granted from Special Dividend	17,865
Options outstanding, Ending Balance, Shares	276,851
Options outstanding, Ending Balance, Weighted Average Exercise Price	$ 17.69
Options outstanding, Ending Balance, Options Exercisable	276,851