Equity - Treasury Stock (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jul. 26, 2017	May 12, 2014
Equity, Class of Treasury Stock [Line Items]
Authorized share amount for repurchase (up to)			$ 10,000,000
Shares repurchased, value	$ 14,693,000
Brokerage commissions	51,000
Remaining authorizations under the repurchase program	$ 15,243,000
Shares reissued from the treasury (in shares)	2,277,073
Shares reissued from the treasury, value	$ 18,659,439
Treasury Stock
Equity, Class of Treasury Stock [Line Items]
Share repurchase (in shares)	1,685,993
Shares repurchased for tax withholding (in shares)	313,563
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Authorized share amount for repurchase (up to)		$ 100,000,000