	First Quarter 2018		Second Quarter 2018		Third Quarter 2018		Fourth Quarter 2018
Net sales	$	1,120,517	$	1,239,856	$	1,150,405	$	1,057,729
Gross profit		411,400		471,310		423,874		381,700
Operating income (1)(2)(3)		103,726		164,688		132,225		49,329
Net income (loss) (4)		33,735		65,922		63,843		(23,283	)
Basic earnings (loss) per share	$	0.18	$	0.34	$	0.33	$	(0.12	)
Diluted earnings (loss) per share	$	0.17	$	0.34	$	0.33	$	(0.12	)

	First Quarter 2017		Second Quarter 2017		Third Quarter 2017		Fourth Quarter 2017
Net sales	$	1,137,285	$	1,174,090	$	1,128,775	$	1,120,432
Gross profit		453,807		471,765		428,605		413,627
Operating income (1)(2)		119,972		136,389		125,428		90,250
Net income (4)		33,562		55,464		51,157		53,581
Basic earnings per share	$	0.17	$	0.29	$	0.27	$	0.28
Diluted earnings per share	$	0.17	$	0.28	$	0.26	$	0.27

(1)

Operating income for the first, second, third and fourth quarters in 2018 included charges related to restructuring costs of $5,450, $7,218, $7,070 and $24,287, respectively. Operating income for the first, second, third and fourth quarters in 2017 included charges related to restructuring costs of $5,388, $13,773, $5,360 and $19,261, respectively.

(2)

Operating income for the first, second, third and fourth quarters in 2018 included charges related to integration and transaction costs of $1,614, $959, $2,647 and $14,314, respectively. Operating income for the first, second, third and fourth quarters in 2017 included charges related to integration and transaction costs of $13,485, $12,684, $12,093 and $9,784, respectively.

(3)	Operating income for the fourth quarter in 2018 included an asset impairment charge of $15,000.

(4)

Net income (loss) for the fourth quarter in 2018 included employee defined benefit plan termination charges of $24,818 and foreign currency losses of $13,952 resulting from an entity liquidation. Net income for the fourth quarter in 2017 included a benefit of $22,358 for the estimated impact of U.S. tax reform and a benefit of $16,740 related to tax law changes in certain foreign jurisdictions.