Preferred Stock and Stockholders' Equity (Details) (USD $)	0 Months Ended	3 Months Ended				12 Months Ended			0 Months Ended		1 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended
	Feb. 26, 2013	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 29, 2012 Series B Convertible Preferred Stock	Nov. 29, 2007 Series B Convertible Preferred Stock	Jan. 31, 2011 Series B Convertible Preferred Stock	Dec. 31, 2012 Series B Convertible Preferred Stock	Nov. 29, 2012 Common Stock	Jan. 31, 2011 Common Stock	Dec. 31, 2013 Treasury Stock	Dec. 31, 2012 Treasury Stock	Dec. 31, 2011 Treasury Stock	Mar. 31, 2014 Subsequent Event	Dec. 31, 2013 Subsequent Event	Dec. 31, 2012 Subsequent Event	Dec. 31, 2011 Subsequent Event
Class of Stock [Line Items]
Preferred stock, shares issued										35,000
Payments for Repurchase of Preferred Stock and Preference Stock										$ 35,000,000
Payments of Stock Issuance Costs										800,000
Stock Repurchased During Period, Shares															412,022		534,101
Convertible Stock Initial Stated Value										$ 1,000
Preferred Stock Accretion Rate per Annum										6.00%
Preferred Stock, Accretion Value for Conversion												1,000
Convertible Preferred Stock, Shares Issued per Aggregate Accretion Value Unit												14.44878
Conversion of Series B preferred stock, shares									34,900		100
Conversion of Series B preferred stock							0	0	47,000,000		120,000
Stock Issued During Period, Shares, Conversion of Convertible Securities													679,168	1,737
Authorized amount under stock repurchase program	100,000,000							45,000,000
Stock Repurchased During Period, Value						29,698,000		21,170,000							29,698,000		21,170,000
Payments for Repurchase of Common Stock						29,698,000		21,170,000								0
Stock Issued During Period, Shares, Treasury Stock Reissued															318,644	433,732	135,230
Reissuance of treasury stock						$ 9,080,000	$ 7,453,000	$ 4,298,000							$ 11,692,000	$ 14,089,000	$ 4,298,000
Dividends declared per common share		$ 0.75	$ 0.75	$ 0.75	$ 0.75	$ 3	$ 0	$ 0										$ 0.75		$ 0	$ 0
Payment date		Dec. 27, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013													Mar. 28, 2014
Declaration date		Oct. 03, 2013	Aug. 02, 2013	May 14, 2013	Feb. 26, 2013													Feb. 25, 2014
Dividends Payable, Date of Record																			Mar. 14, 2014