Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013
Segment information
Revenues	$ 2,743,445	$ 1,338,208	$ 5,723,339	$ 2,800,154
Depreciation and amortization	35,494	18,747	83,279	41,335
Operating income (loss)	41,169	50,223	43,772	53,734
Additions to property, plant and equipment including acquisitions (accrual basis)	195,195	110,207	341,493	310,926
Total assets	4,476,978		4,476,978		2,291,347
Long-lived assets, net	2,557,648		2,557,648		1,522,686
Crude oil logistics
Segment information
Depreciation and amortization	5,827	1,904	13,841	3,844
Operating income (loss)	(6,424)	11,407	6,069	17,226
Additions to property, plant and equipment including acquisitions (accrual basis)	153,209	53,913	188,671	82,227
Total assets	1,888,885		1,888,885		801,030
Long-lived assets, net	907,799		907,799		356,750
Water solutions
Segment information
Depreciation and amortization	18,258	7,235	37,052	10,285
Operating income (loss)	982	5,499	6,938	10,046
Additions to property, plant and equipment including acquisitions (accrual basis)	11,533	34,227	81,715	130,584
Total assets	862,633		862,633		466,462
Long-lived assets, net	835,216		835,216		453,986
Natural gas liquids logistics
Segment information
Number of operating divisions			2
Depreciation and amortization	2,759	2,265	8,135	7,715
Operating income (loss)	40,601	25,090	53,091	36,492
Additions to property, plant and equipment including acquisitions (accrual basis)	21,267	8,452	49,583	13,896
Total assets	767,493		767,493		474,141
Long-lived assets, net	276,574		276,574		238,192
Retail propane
Segment information
Number of operating divisions			2
Depreciation and amortization	7,344	6,987	21,455	18,915
Operating income (loss)	21,696	16,437	15,672	9,797
Additions to property, plant and equipment including acquisitions (accrual basis)	8,915	9,816	20,407	67,063
Total assets	529,671		529,671		513,301
Long-lived assets, net	442,276		442,276		441,762
Corporate and other
Segment information
Operating income (loss)	(15,686)	(8,210)	(37,998)	(19,827)
Additions to property, plant and equipment including acquisitions (accrual basis)	271	3,799	1,117	17,156
Total assets	428,296		428,296		36,413
Long-lived assets, net	95,783		95,783		31,996
Other
Segment information
Depreciation and amortization	1,306	356	2,796	576
Operating segment | Crude oil logistics | Crude oil sales
Segment information
Revenues	1,319,290	683,054	3,260,885	1,468,731
Operating segment | Crude oil logistics | Other revenues
Segment information
Revenues	6,198	1,174	25,927	3,708
Operating segment | Water solutions | Water treatment and disposal
Segment information
Revenues	36,282	20,563	83,793	34,799
Operating segment | Water solutions | Water transportation
Segment information
Revenues	5,490	2,243	12,682	5,758
Operating segment | Natural gas liquids logistics | Other revenues
Segment information
Revenues	7,695	8,822	25,809	17,143
Operating segment | Natural gas liquids logistics | Propane sales
Segment information
Revenues	518,541	255,157	833,815	477,981
Operating segment | Natural gas liquids logistics | Other product sales
Segment information
Revenues	336,654	286,598	895,113	626,360
Operating segment | Retail propane | Other revenues
Segment information
Revenues	11,377	10,585	27,275	26,382
Operating segment | Retail propane | Propane sales
Segment information
Revenues	112,570	84,258	199,912	162,049
Operating segment | Retail propane | Distillate sales
Segment information
Revenues	37,648	33,062	66,079	55,685
Operating segment | Corporate and other
Segment information
Revenues	423,159	1,381	426,118	2,842
Elimination of intersegment sales
Segment information
Revenues	$ (71,459)	$ (48,689)	$ (134,069)	$ (81,284)