Summary of Significant Accounting Policies (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended	1 Months Ended		3 Months Ended
	May 05, 2014	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2014
Summary of Significant Accounting Policies (Textual) [Abstract]
Stock split conversion ratio	2
Cost of shares repurchased		$ 25.0
Current repurchase program
Summary of Significant Accounting Policies (Textual) [Abstract]
Authorized amount from board of directors for share repurchase				250	250
Share repurchase program expiry date				Dec. 31, 2015
Shares repurchased under the program (in shares)		721,040
Cost of shares repurchased		25.0
Shares repurchased settled in subsequent month			7.0
Prior repurchase program
Summary of Significant Accounting Policies (Textual) [Abstract]
Shares repurchased under the program (in shares)					276,546
Cost of shares repurchased					$ 10.0