Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Net income	$ 14,507	$ 12,930	$ 11,114	$ 18,330	$ 13,850
Less income allocated to non-controlling interests	(95)				(88)
Less income allocated to participating securities:
Non-forfeitable dividends on participating securities	(137)				(120)
Net income available to common stockholders	14,275				13,642
Net income for diluted net income per share	$ 14,275				$ 13,642
Reconciliation of shares
Shares for basic net income per share	39,199				39,100
Effect of dilutive securities:
Total effect of dilutive securities (in shares)	150				79
Shares for diluted net income per share	39,349				39,179
Basic net income per share (in dollars per share)	$ 0.36				$ 0.35
Diluted net income per share (in dollars per share)	$ 0.36				$ 0.35
Stock options
Effect of dilutive securities:
Stock options and performance-based stock units (in shares)					1
Performance-based stock units
Effect of dilutive securities:
Stock options and performance-based stock units (in shares)	150				78