Supplemental Financial Information (Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statement of Income Captions [Line Items]
Net income (loss)	$ (7,752)	$ 13,786	$ 18,612	$ 9,029	$ 220	$ 13,632	$ 4,087	$ 5,509	$ 33,675	$ 23,448	$ (81,824)
Other comprehensive income:
Foreign currency translation adjustment									6,945	(6,228)	(4,364)
Unrealized loss on cash flow hedges, net of tax									0	143	(143)
Adjustment to retirement benefit liability, net of tax									55	49	(24)
Adjustment to post-retirement healthcare benefit liability, net of tax									695	171	(1,435)
Other comprehensive income (loss)									7,695	(5,865)	(5,966)
Total comprehensive income (loss)									41,370	17,583	(87,790)
Gibraltar Industries, Inc.
Condensed Statement of Income Captions [Line Items]
Net income (loss)									32,998	27,036	(80,650)
Other comprehensive income:
Foreign currency translation adjustment									0	0	0
Unrealized loss on cash flow hedges, net of tax										0	0
Adjustment to retirement benefit liability, net of tax									0	0	0
Adjustment to post-retirement healthcare benefit liability, net of tax									0	0	0
Other comprehensive income (loss)									0	0	0
Total comprehensive income (loss)									32,998	27,036	(80,650)
Guarantor Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss)									57,857	36,401	(71,191)
Other comprehensive income:
Foreign currency translation adjustment									0	0	0
Unrealized loss on cash flow hedges, net of tax										143	(143)
Adjustment to retirement benefit liability, net of tax									55	34	3
Adjustment to post-retirement healthcare benefit liability, net of tax									695	171	(1,435)
Other comprehensive income (loss)									750	348	(1,575)
Total comprehensive income (loss)									58,607	36,749	(72,766)
Non-Guarantor Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss)									3,699	(1,213)	2,929
Other comprehensive income:
Foreign currency translation adjustment									6,945	(6,228)	(4,364)
Unrealized loss on cash flow hedges, net of tax										0	0
Adjustment to retirement benefit liability, net of tax									0	15	(27)
Adjustment to post-retirement healthcare benefit liability, net of tax									0	0	0
Other comprehensive income (loss)									6,945	(6,213)	(4,391)
Total comprehensive income (loss)									10,644	(7,426)	(1,462)
Eliminations
Condensed Statement of Income Captions [Line Items]
Net income (loss)									(60,879)	(38,776)	67,088
Other comprehensive income:
Foreign currency translation adjustment									0	0	0
Unrealized loss on cash flow hedges, net of tax										0	0
Adjustment to retirement benefit liability, net of tax									0	0	0
Adjustment to post-retirement healthcare benefit liability, net of tax									0	0	0
Other comprehensive income (loss)									0	0	0
Total comprehensive income (loss)									$ (60,879)	$ (38,776)	$ 67,088