Stock-Based Compensation (Restricted Stock Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) award shares	Dec. 31, 2017 USD ($) award shares	Dec. 31, 2016 USD ($) award shares
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (in shares) | shares	315,000	308,000	235,000
Compensation expense, restricted stock | $	$ 2,300	$ 2,000	$ 1,600
Unrecognized compensation cost | $	$ 2,800
Unrecognized compensation cost, period for recognition (in years)	1 year 8 months
Fair value of restricted stock that vested | $	$ 2,300
Restricted Stock | Independent Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (in shares) | shares	118,555	120,878	72,771
Restricted Stock | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (in shares) | shares	315,199	308,289	234,965
Vesting period	3 years
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (in shares) | shares	450,000	399,000	312,000
Types of performance-based RSUs | award		2,000	2,000
Targeted number of units outstanding (in shares) | shares	443,127	379,381	379,582
Performance-based RSUs | Key Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Types of performance-based RSUs | award	2
Payout range minimum (as a percent)	0.00%
Payout range maximum (as a percent)	200.00%
Time-vested RSUs | Key Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (in shares) | shares	17,836	264,723	28,938
Vesting period	3 years	3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition (in years)	1 year 1 month
Estimate of future expense for all types of RSUs outstanding | $	$ 3,600
Total cash paid for vesting and dividend payments | $	3,700
Recognized compensation expense related to RSUs for employees and directors, before capitalization or income tax benefit, if any | $	$ 4,600	$ 7,000	$ 6,400