CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (2,685)	$ 122,265	$ 161,780	$ 145,689
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion	10,569	50,024	49,293	41,439
Change in fair value of contingent consideration	705	(4,411)	(3,574)	1,815
Provision for (recovery of) doubtful accounts, net	(169)	5,120	1,107	125
Deferred tax provision	(2,736)	8,167	9,970	(4,092)
Stock compensation	2,865	6,622	13,524	13,136
Gain on sale of assets	0	(1,338)	0	0
Impairment of long-lived assets	0	9,773	0	0
Restructuring costs	0	24,856	0	0
Other	111	56	2,969	1,306
Changes in operating assets and liabilities:
Trade accounts receivable	77,983	(23,545)	(36,885)	6,618
Inventories	49,272	(61,492)	(26,748)	40,580
Prepaid expenses and other current assets	68,837	(3,681)	(10,376)	(58,554)
Income tax receivable	0	(8,286)	(15,170)	0
Other assets	(758)	(3,082)	(144)	(4,290)
Trade accounts payable	(74,898)	14,775	8,912	21,251
Contingent consideration	(2,974)	(819)	(364)	(6,458)
Accrued expenses	(33,666)	(16,221)	3,761	33,556
Income taxes payable	(46,545)	(397)	4,883	24,386
Long-term liabilities	1,998	7,195	6,716	5,618
Net cash provided by operating activities	47,909	125,581	169,654	262,125
Cash flows from investing activities:
Purchases of property and equipment	(17,603)	(65,356)	(91,147)	(79,829)
Purchases of tangible, intangible, and other assets, net	(30)	(4,700)	(9,489)	(5,368)
Proceeds from sale of assets	0	2,835	0	0
Net cash used in investing activities	(17,633)	(67,221)	(100,636)	(85,197)
Cash flows from financing activities:
Proceeds from issuance of short-term borrowings	0	449,200	199,784	320,728
Repayments of short-term borrowings	(3,000)	(387,120)	(201,705)	(344,000)
Cash paid for shares withheld for taxes	(3,752)	(3,691)	(5,674)	(6,736)
Excess tax benefit from stock compensation	0	471	4,197	2,071
Cash received from issuances of common stock	0			52
Cash paid for repurchases of common stock	0	(94,200)	(107,239)	0
Contingent consideration paid	(15,852)	(445)	(115)	(22,628)
Loan origination costs on short-term borrowings	0	(62)	(818)	0
Proceeds from mortgage loan	0	0	33,931	0
Mortgage loan origination costs		0	(338)
Repayment of mortgage principal	0	(493)	(283)	0
Net cash used in financing activities	(22,604)	(36,340)	(78,260)	(50,513)
Effect of exchange rates on cash	291	(1,207)	(10,703)	463
Net change in cash and cash equivalents	7,963	20,813	(19,945)	126,878
Cash and cash equivalents at beginning of period	237,125	225,143	245,088	110,247
Cash and cash equivalents at end of period	245,088	245,956	225,143	237,125
Cash paid during the period for:
Income taxes	48,040	29,916	53,504	39,122
Interest	187	4,640	4,315	2,586
Non-cash investing and financing activities:
Accrued for purchases of property and equipment	4,265	2,640	3,419	2,283
Accrued for asset retirement obligations	19	1,394	786	1,936
Accrued for shares withheld for taxes	0	919	0	3,702
Write-off for shares exercised with a tax deficit	$ 0	$ 0	$ 0	$ 1,752