Stockholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 31, 2012	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2015
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 20
Preferred stock, shares outstanding (in shares)	0	0
Stock repurchased during period	$ 10,000,000	$ 6,864,000	$ 4,999,000
Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	500,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	30,000
Preferred stock, voting rights	Each share of the Series A Preferred Stock shall entitle the holder to one thousand votes
Stock Repurchase Program 2012 [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount				5,000,000
Stock repurchased during period (in shares)		30,601	312,527
Stock repurchased during period		900,000	4,100,000
Stock repurchase program, remaining authorized amount		0
Stock Repurchase Program 2013 [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount					6,000,000
Stock repurchased during period (in shares)		179,372
Stock repurchased during period		6,000,000
Stock repurchase program, remaining authorized amount		0
Stock Repurchase Program 2014 [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount						10,000,000
Stock repurchased during period (in shares)	284,284
Stock repurchased during period	10,000,000
Stock repurchase program, remaining authorized amount	0
Stock Repurchase Program 2015 [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount							$ 10,000,000