Equity-Based Compensation (Summary of Compensation Expense Connection with Awards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Expense recognized under the Prior Plan	$ 1,059	$ 1,937	$ 1,953
Expense recognized under the Plan	5,643	3,993	1,938
Expense recognized under the Non-Employee Directors Plan	420	443	0
Total stock compensation expense	7,122	6,373	3,891
Tax benefits recognized related to stock compensation expense	$ 2,133	$ 2,485	$ 1,518