CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Paid-in capital	Treasury stock	Accumulated other comprehensive income (loss)	Retained earnings (deficit)
Balance, beginning of period at Dec. 31, 2014		$ 340,047	$ 1,663,592	$ (32,937)	$ (81,341)	$ (852,458)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net common stock issued under share-based compensation plans		32	38
Reissuance of treasury stock, net			(7,251)	29,575		(29,494)
Tax benefit from share-based compensation			2,568
Equity compensation			3,264
Reacquisition of convertible junior subordinated debentures-equity component			0
Other comprehensive income	$ 16,849				16,849
Net income	133,076					133,076
Balance, end of period at Mar. 31, 2015	1,185,560	340,079	1,662,211	(3,362)	(64,492)	(748,876)
Balance, beginning of period at Dec. 31, 2015	2,236,140	340,097	1,670,238	(3,362)	(60,880)	290,047
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net common stock issued under share-based compensation plans		979	(5,949)
Reissuance of treasury stock, net			0	0		0
Tax benefit from share-based compensation			115
Equity compensation			3,129
Reacquisition of convertible junior subordinated debentures-equity component			(9,750)
Other comprehensive income	49,544				49,544
Net income	69,191					69,191
Balance, end of period at Mar. 31, 2016	$ 2,343,399	$ 341,076	$ 1,657,783	$ (3,362)	$ (11,336)	$ 359,238