Employee Benefit Plans - Changes in projected benefit obligation, plan assets and funded status (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Change in projected benefit obligation
Projected benefit obligation at beginning of year	$ 46,569	$ 46,811
Service cost	2,457	2,729	2,093
Interest cost	2,333	2,058	1,957
Benefits paid	(1,092)	(796)
Actuarial (gain) loss	7,332	(4,233)
Projected benefit obligation at end of year	57,599	46,569	46,811
Change in plan assets
Fair value of plan assets at beginning of year	31,501	27,856
Actual return on plan assets	4,339	1,888
Employer contributions	4,833	2,553
Benefits paid	(1,092)	(796)
Fair value of plan assets at end of year	39,581	31,501	27,856
Funded status at end of year	$ (18,018)	$ (15,068)