The owner of the landmark North Charleston paper mill is reporting record first-quarter earnings and revenue, meeting Wall Street’s expectations.

KapStone Paper and Packaging Corp. netted $18 million for the period, up 19 percent from the first three months of 2012. Sales increased 7 percent to $320 million, as per-ton prices for containerboard rose by that same amount year over year.

Excluding onetime items, KapStone’s profit was $20.4 million, or 42 cents a share. On average, eight analysts told Thomson Reuters that they expected the company to earn that amount before special charges are subtracted from the bottom line.

“Our operations performed well during the quarter, propelling the company to record first quarter results,” CEO Roger W. Stone said in statement.

Stone said the improved financial performance was offset by higher costs from labor and outages, as well as charges from new information systems and from startup expenses for a newly opened plant in Aurora, Ill.

“With our strong cash flows and balance sheet KapStone is in an excellent position to continue growing profitably.” Stone said.

Northbrook, Ill-based KapStone owns the large blue paper mill on the Cooper River near U.S. Interstate 526. It bought that business and a Summerville-based saw mill operation for $471 million from MeadWestvaco Corp. in 2008.

The company released its earnings after U.S stock markets had closed on Tuesday.