Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities:
Net income	$ 11,258	$ 17,567	$ 16,331
Reconciliation of net income to cash provided by operating activities:
Depreciation and amortization	40,879	14,349	13,227
Impairment of long-lived assets	279	293	0
Provision (benefit) for deferred income taxes	(3,514)	(266)	1,930
Equity compensation expense	1,544	1,459	1,905
Provision for doubtful accounts	185	279	94
Loss on sale of property, plant, and equipment	484	20	205
Other non-cash charges and (credits)	925	325	281
Financing expense	6,750	0	0
Changes in operating assets and liabilities:
Accounts receivable	(23,943)	(5,534)	(7,477)
Inventories	(30,972)	2,097	1,111
Prepaid expenses and other current assets	(8,031)	1,888	(1,887)
Accounts payable and accrued expenses	49,152	(3,342)	5,390
Other	(177)	0	(1)
Net cash provided by operating activities	44,819	29,135	31,109
Investing activities:
Purchases of property, plant, and equipment, net	(48,137)	(24,574)	(20,947)
Acquisition of CSI	(825,000)	0	0
Advances and other investing activities	(805)	0	(39)
Net cash used in investing activities	(873,942)	(24,574)	(20,986)
Financing activities:
Proceeds from long-term debt, net	602,858	19,909	10,050
Payments of long-term debt	(93,584)	0	0
Proceeds from issuance of partnership common units, net of underwriters' discount	395,794	0	0
Distributions	(36,687)	(26,969)	(24,732)
Financing costs	(22,486)	916
Contribution from general partner	8,405
Deferred financing cost and other financing activities	(22,486)	(916)	0
Net cash (used in) provided by financing activities	854,300	(7,976)	(14,682)
Effect of exchange rate changes on cash	(588)	(74)	49
Increase (decrease) in cash and cash equivalents	24,589	(3,489)	(4,510)
Cash and cash equivalents at beginning of period	9,477	12,966	17,476
Cash and cash equivalents at end of period	34,066	9,477	12,966
Supplemental cash flow information:
Taxes paid	$ 2,247	$ 2,204	$ 1,059