Retirement Benefit Plans

3 Months Ended

Sep. 30, 2015

6. Retirement Benefit Plans

The Company sponsors various retirement benefit plans including qualified and nonqualified defined benefit pension plans for its employees. The components of net periodic pension expense are as follows (in thousands):

	Three Months Ended September 30,
	2014		2015
Service cost	$	288	$	204
Interest cost	—		9
Amortization of prior service cost	202		105

Net periodic pension expense	$	490	$	318

For the three months ended September 30, 2014, the Company made contributions of $1.0 million to these defined benefit plans; while no contributions were made during the three months ended September 30, 2015.

In addition, the Company maintains various defined contribution plans. For the three months ended September 30, 2014 and 2015, the Company made contributions of $1.2 and $1.1 million, respectively, to these defined contribution plans.