Organization and Significant Accounting Policies ASC 606 Adjustments Statements of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 1,382,818	$ 1,200,181	$ 757,338
Net sales (1)	$ 355,794	$ 350,175	$ 349,233	$ 327,616	$ 318,091	$ 306,576	$ 301,568	$ 273,946	1,382,818	1,200,181	757,338
Cost of sales (1)									924,276	860,744	571,944
Research and development (1)									44,612	39,114	26,693
Operating income (loss)	54,057	61,616	50,000	35,176	21,646	32,002	31,597	27,607	200,849	112,852	34,968
Income tax expense (benefit) (1)									(39,460)	9,132	4,294
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest									206,587	254,127	47,157
Net Income (Loss) Available to Common Stockholders, Basic	$ 93,420	$ 40,806	$ 37,141	$ 35,220	$ 2,280	$ 18,589	$ 12,819	$ 220,439	$ 206,587	$ 254,127	$ 47,157
Earnings Per Share, Basic	$ 1.60	$ 0.70	$ 0.64	$ 0.61	$ 0.04	$ 0.33	$ 0.26	$ 4.65	$ 3.57	$ 4.81	$ 1.01
Earnings Per Share, Diluted	$ 1.58	$ 0.69	$ 0.63	$ 0.60	$ 0.04	$ 0.32	$ 0.22	$ 3.82	$ 3.50	$ 4.33	$ 0.85
Restatement Adjustment | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										$ 255	$ (453)
Cost of sales (1)										1,211	1,080
Research and development (1)										(505)	(705)
Operating income (loss)										(451)	(828)
Income tax expense (benefit) (1)										(49)	4
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										$ (402)	$ (832)
Earnings Per Share, Basic										$ (0.01)	$ (0.02)
Earnings Per Share, Diluted										$ (0.01)	$ (0.02)
Scenario, Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										$ 1,199,926	$ 757,791
Cost of sales (1)										859,533	570,864
Research and development (1)										39,619	27,398
Operating income (loss)										113,303	35,796
Income tax expense (benefit) (1)										9,181	4,290
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										$ 254,529	$ 47,989
Earnings Per Share, Basic										$ 4.82	$ 1.03
Earnings Per Share, Diluted										$ 4.34	$ 0.87