Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance (shares) at Dec. 31, 2014		78,516	13,809
Stockholders' equity - beginning balance at Dec. 31, 2014	$ 452,518	$ 92	$ (200,424)	$ 345,732	$ 325,470	$ (18,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	11,186			11,186
Tax shortfall from share-based plans	(2,841)			(2,841)
Exercises of stock options and issuance of restricted stock awards (shares)		(810)	(34)
Exercises of stock options and issuance of restricted stock awards	1,603	$ 2	$ 2,437	(836)
Repurchases of common stock (shares)		6,475	6,475
Repurchases of common stock	(85,926)		$ (85,926)
Series A preferred dividends	(11,833)				(11,833)
Series A preferred accretion	(2,978)				(2,978)
Net income (loss)	(83,196)				(83,196)
Other comprehensive gain	(32,561)					(32,561)
Ending balance (shares) at Dec. 31, 2015		72,851	20,250
Stockholders' equity - ending balance at Dec. 31, 2015	245,972	$ 94	$ (283,913)	353,241	227,463	(50,913)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	10,736			10,736
Exercises of stock options and issuance of restricted stock awards (shares)		(749)	(37)
Exercises of stock options and issuance of restricted stock awards	96	$ 0	$ (324)	420
Series A preferred dividends	(12,000)				(12,000)
Series A preferred accretion	(3,244)				(3,244)
Net income (loss)	(16,494)				(16,494)
Other comprehensive gain	(4,683)					(4,683)
Ending balance (shares) at Dec. 31, 2016		73,600	20,287
Stockholders' equity - ending balance at Dec. 31, 2016	220,383	$ 94	$ (284,237)	364,397	195,725	(55,596)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	11,619			11,619
Exercises of stock options and issuance of restricted stock awards (shares)		(850)	(41)
Exercises of stock options and issuance of restricted stock awards	(3,045)	$ 1	$ (75)	(2,971)
Repurchases of common stock (shares)		5,659	5,659
Repurchases of common stock	(50,000)		$ (50,000)
Series A preferred dividends	(12,000)				(12,000)
Series A preferred accretion	(3,532)				(3,532)
Net income (loss)	10,238
Other comprehensive gain	12,202					12,202
Ending balance (shares) at Dec. 31, 2017		68,791	25,987
Stockholders' equity - ending balance at Dec. 31, 2017	$ 185,865	$ 95	$ (334,312)	$ 373,045	$ 190,431	$ (43,394)