Consolidated Statements of Operations (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 617,944	$ 650,238	$ 1,225,477	$ 1,305,186
Cost of sales, including warehousing, distribution and occupancy	410,209	430,455	810,868	865,541
Gross profit	207,735	219,783	414,609	439,645
Selling, general, and administrative	158,531	159,540	319,261	325,567
Long-lived asset impairments	0	19,356	0	19,356
Other loss (income), net	320	(486)	75	(1,619)
Operating income	48,884	41,373	95,273	96,341
Interest expense, net	32,943	16,067	54,716	31,961
Loss on debt refinancing	0	0	16,740	0
Income before income taxes	15,941	25,306	23,817	64,380
Income tax expense	2,600	8,662	4,286	22,992
Net income	$ 13,341	$ 16,644	$ 19,531	$ 41,388
Earnings per share
Basic (in dollars per share)	$ 0.16	$ 0.24	$ 0.23	$ 0.61
Diluted (in dollars per share)	$ 0.16	$ 0.24	$ 0.23	$ 0.61
Weighted average common shares outstanding
Basic (in shares)	83,332	68,287	83,282	68,267
Diluted (in shares)	83,409	68,362	83,389	68,331