Condensed Consolidating Financial Statements - Cash Flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities	$ 71,667	$ 32,365	$ 24,402
Investing activities:
Capital expenditures	(25,617)	(20,469)	(22,232)
Change in restricted cash	0	1,802	11,509
Proceeds from sale of assets	(19)	(971)	(4,788)
Proceeds from sale of discontinued operations	0	0	9,564
Acquisitions, net of cash received	0	(2,892)	0
Net cash provided by (used in) investing activities	(25,598)	(20,588)	3,629
Financing activities:
Proceeds from revolving line of credit	12,000	10,000	42,340
Payments of revolving line of credit	(12,000)	(9,600)	(27,342)
Deferred acquisition payments	0	(3,000)	(19,527)
Proceeds from issuance of debt	2,314	0	0
Payment of long-term debt	(2,428)	(481)	(21,733)
Proceeds from exercise of stock options	1,133	0	24
Purchase of treasury stock	(1,144)	(722)	(630)
Net cash provided by (used in) financing activities	(125)	(3,803)	(26,868)
Net increase (decrease) in cash and cash equivalents	45,944	7,974	1,163
Effect of foreign currency fluctuations on cash	(1,174)	668	(2,730)
Cash and cash equivalents at beginning of fiscal year	65,004	56,362	57,929
Cash and cash equivalents at end of fiscal year	109,774	65,004	56,362
Reclassifications and Eliminations
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities	0	0	0
Investing activities:
Capital expenditures	0	0	0
Change in restricted cash	0	0	0
Proceeds from sale of assets	0	0	0
Proceeds from sale of discontinued operations			0
Acquisitions, net of cash received	0	0
Net cash provided by (used in) investing activities	0	0	0
Financing activities:
Proceeds from revolving line of credit	0	0	0
Payments of revolving line of credit	0	0	0
Deferred acquisition payments	0	0	0
Payment of long-term debt	0	0	0
Proceeds from exercise of stock options	0		0
Purchase of treasury stock	0	0
Net cash provided by (used in) financing activities	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Effect of foreign currency fluctuations on cash	0	0	0
Cash and cash equivalents at beginning of fiscal year	0	0	0
Cash and cash equivalents at end of fiscal year	0	0	0
Parent
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities	3,313	3,722	39,575
Investing activities:
Capital expenditures	0	0	0
Change in restricted cash	0	0	0
Proceeds from sale of assets	0	0	0
Proceeds from sale of discontinued operations			0
Acquisitions, net of cash received	0	0
Net cash provided by (used in) investing activities	0	0	0
Financing activities:
Proceeds from revolving line of credit	0	0	0
Payments of revolving line of credit	0	0	0
Deferred acquisition payments	0	(3,000)	(18,527)
Payment of long-term debt	(1,870)	0	(20,417)
Proceeds from exercise of stock options	1,133		24
Purchase of treasury stock	(1,144)	(722)	(630)
Net cash provided by (used in) financing activities	(1,881)	(3,722)	(39,550)
Net increase (decrease) in cash and cash equivalents	1,432	0	25
Effect of foreign currency fluctuations on cash	0	0	(1)
Cash and cash equivalents at beginning of fiscal year	640	640	616
Cash and cash equivalents at end of fiscal year	2,072	640	640
Guarantor Subsidiaries
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities	34,778	15,107	(4,085)
Investing activities:
Capital expenditures	(10,295)	(9,550)	(12,930)
Change in restricted cash	0	1,802	11,509
Proceeds from sale of assets	(13)	(248)	(2,403)
Proceeds from sale of discontinued operations			0
Acquisitions, net of cash received	0	(2,892)
Net cash provided by (used in) investing activities	(10,282)	(10,392)	982
Financing activities:
Proceeds from revolving line of credit	12,000	8,000	37,340
Payments of revolving line of credit	0	(9,600)	(22,342)
Deferred acquisition payments	0	0	(1,000)
Payment of long-term debt	0	0	0
Proceeds from exercise of stock options	0		0
Purchase of treasury stock	0	0	0
Net cash provided by (used in) financing activities	12,000	(1,600)	13,998
Net increase (decrease) in cash and cash equivalents	36,496	3,115	10,895
Effect of foreign currency fluctuations on cash	0	0	(1)
Cash and cash equivalents at beginning of fiscal year	36,209	33,094	22,200
Cash and cash equivalents at end of fiscal year	72,705	36,209	33,094
Non-Guarantor Subsidiaries
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities	33,576	13,536	(11,088)
Investing activities:
Capital expenditures	(15,322)	(10,919)	(9,302)
Change in restricted cash	0	0	0
Proceeds from sale of assets	(6)	(723)	(2,385)
Proceeds from sale of discontinued operations			9,564
Acquisitions, net of cash received	0	0
Net cash provided by (used in) investing activities	(15,316)	(10,196)	2,647
Financing activities:
Proceeds from revolving line of credit	0	2,000	5,000
Payments of revolving line of credit	(12,000)	0	(5,000)
Deferred acquisition payments	0	0	0
Proceeds from issuance of debt	2,314
Payment of long-term debt	(558)	(481)	(1,316)
Proceeds from exercise of stock options	0		0
Purchase of treasury stock	0	0	0
Net cash provided by (used in) financing activities	(10,244)	1,519	(1,316)
Net increase (decrease) in cash and cash equivalents	8,016	4,859	(9,757)
Effect of foreign currency fluctuations on cash	(1,174)	668	(2,728)
Cash and cash equivalents at beginning of fiscal year	28,155	22,628	35,113
Cash and cash equivalents at end of fiscal year	$ 34,997	$ 28,155	$ 22,628