Stock Based Compensation (Stock based compensation expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	$ 2,154	$ 1,804	$ 3,385	$ 3,693
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	90	284	226	976
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	1,600	1,136	2,417	2,015
Performance-based restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	378	121	565	123
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation	$ 86	$ 263	$ 177	$ 579