Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Organization Consolidation And Presentation [Line Items]
Cash equivalents	$ 0				$ 0		$ 4,400,000
Repurchases of common stock under share repurchase program (shares)	0		100,000		100,000	1,000,000.0
Weighted average cost of repurchased shares			$ 18.16		$ 16.20	$ 17.11
Repurchases of common stock under share repurchase program		$ 1,416,000	$ 737,000	$ 15,709,000	$ 1,400,000	$ 16,400,000
Share repurchase program authorized	$ 75,000,000.0				75,000,000.0
Remaining under current repurchase authorization	$ 54,200,000				$ 54,200,000