Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended	1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Current repurchase program	Mar. 31, 2014 Current repurchase program	Mar. 31, 2014 Prior repurchase program	Mar. 31, 2013 Prior repurchase program
Summary of Significant Accounting Policies (Textual) [Abstract]
Authorized amount from board of directors for share repurchase		$ 250,000,000		$ 200,000,000
Share repurchase program effective date		Mar. 07, 2014
Share repurchase program expiry date		Dec. 31, 2015
Shares repurchased under the program			138,273		0
Cost of shares repurchased	10,000,000		10,000,000
Shares repurchased settled in subsequent month		$ 2,500,000