Segment and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Segment financial information
Net sales	$ 667,187	$ 608,123	$ 1,347,888	$ 1,232,971
Operating income for reportable segments	46,715	37,856	98,552	81,275
Assets used in business	1,405,882	1,294,516	1,405,882	1,294,516	$ 1,387,595
Depreciation and amortization of property	4,081	3,837	8,008	7,487
Capital expenditures	5,124	3,711	11,460	6,710
Operating Segments [Member]
Segment financial information
Operating income for reportable segments	43,830	31,787	90,842	69,261
Service Center Based Distribution [Member]
Segment financial information
Net sales	555,607	514,334	1,124,520	1,043,564
Operating income for reportable segments	30,006	22,087	63,728	49,083
Assets used in business	1,199,704	1,146,232	1,199,704	1,146,232
Depreciation and amortization of property	3,802	3,608	7,471	7,024
Capital expenditures	4,822	3,344	10,370	6,268
Fluid Power Businesses [Member]
Segment financial information
Net sales	111,580	93,789	223,368	189,407
Operating income for reportable segments	13,824	9,700	27,114	20,178
Assets used in business	206,178	148,284	206,178	148,284
Depreciation and amortization of property	279	229	537	463
Capital expenditures	$ 302	$ 367	$ 1,090	$ 442