Stock repurchase program (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 28, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount	$ 20,000
Share repurchase program, term	18 months
Repurchase of common stock		$ 5,300			$ 9,353	$ 1,303
Share repurchase program, shares repurchased (in shares)		925,624			1,692,207
Average purchase price per share (in dollars per share)		$ 5.76			$ 5.53
Share repurchase program, remaining authorized stock repurchases, amount		$ 9,300			$ 9,300
Stock repurchases		5,334	$ 4,019	$ 1,303
Additional Paid-in Capital
Equity, Class of Treasury Stock [Line Items]
Stock repurchases		3,167	2,623	714	5,800
Retained Earnings
Equity, Class of Treasury Stock [Line Items]
Stock repurchases		$ 2,166	$ 1,395	$ 589	$ 3,600