Shareholders' Equity - Preferred stock authorized for issuance (Details)	Jun. 30, 2018 $ / shares shares
Voting Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares authorized | shares	12,500,000.0
Preferred Stock, par value (in USD per share) | $ / shares	$ 0
Nonvoting Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares authorized | shares	12,500,000.0
Preferred Stock, par value (in USD per share) | $ / shares	$ 0