Retirement Benefit Plans

3 Months Ended

Sep. 30, 2016

8. 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,
	2015		2016
Service cost	$	204	$	224
Interest cost	9		7
Amortization of prior service cost	105		70

Net periodic pension expense	$	318	$	301

For the three months ended September 30, 2015 and 2016, the Company made no contributions to these defined benefit plans.

In addition, the Company maintains various defined contribution plans. For the three months ended September 30, 2015 and 2016, the Company made contributions of $1.1 and $1.2 million, respectively, to these defined contribution plans.