Employee Benefits and Share-Based Compensation - Employee Stock Purchase Plan (ESPP) Activity (Details) - Jun. 30, 2015 - 1997 Employee Stock Purchase Plan [Member] - Employee Stock Purchase Plan [Member] - USD ($) $ in Millions	Total
Share-Based Arrangements with Employees and Nonemployees [Line Items]
Unrecognized compensation cost	$ 2.2
Weighted average period of compensation cost recognized	1 month 6 days