Earnings Per Share (Basic and Diluted EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income attributable to common stockholders		$ 22,029	$ 20,350
Weighted average common shares outstanding, basic (in shares)		66,839	66,782
Weighted average common shares outstanding, diluted (in shares)		67,643	67,282
Basic income per common share (in dollars per share)		$ 0.33	$ 0.30
Diluted income per common share (in dollars per share)		$ 0.33	$ 0.30
Restricted stock units [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock based payment arrangements (in shares)	[1]	670	415
Stock options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock based payment arrangements (in shares)		134	85

[1] Includes service-based and contingently issuable performance-based restricted stock units.