CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated (Deficit) [Member]
Beginning balance at Dec. 31, 2011	$ 636,683	$ 141,000	$ 8	$ 743,780	$ (4,593)	$ (243,512)
Beginning balance, shares at Dec. 31, 2011		141,000	82,362,000
Net income	72,639					72,639
Issuance of stock, net	31,953		1	31,952
Issuance of stock, net, shares			2,966,000
Exercise of stock options	2,802			2,802
Exercise of stock options, shares			397,000
Stock-based compensation	1,939			1,939
Stock-based compensation, shares			183,000
Restricted stock grants, net	4,379
Restricted stock grants, net, shares	557,000
Dividends on preferred stock	(3,793)					(3,793)
Other comprehensive (loss) income, net	12,819				12,819
Ending balance at Dec. 31, 2012	759,421	141,000	9	784,852	8,226	(174,666)
Ending balance, shares at Dec. 31, 2012		141,000	86,465,000
Net income	114,965					114,965
Exercise of stock options	4,595			4,595
Exercise of stock options, shares			440,000
Stock-based compensation	3,547			3,547
Stock-based compensation, shares			131,000
Restricted stock grants, net	4,152			4,152
Restricted stock grants, net, shares			150,000
Dividends on preferred stock	(1,410)					(1,410)
Other comprehensive (loss) income, net	(29,772)				(29,772)
Ending balance at Dec. 31, 2013	855,498	141,000	9	797,146	(21,546)	(61,111)
Ending balance, shares at Dec. 31, 2013		141,000	87,186,000
Net income	147,951					147,951
Issuance of stock, net	13,746			13,746
Redeemed preference shares		(70,500)
Stock Redeemed or Called During Period, Value	(70,500)	(70,500)
Issuance of stock, net, shares			548,122
Exercise of stock options	8,294			8,294
Exercise of stock options, shares	625,000		625,000
Stock-based compensation	2,913			2,913
Stock-based compensation, shares			86,000
Restricted stock grants, net	6,228			6,228
Restricted stock grants, net, shares			246,000
Dividends on preferred stock	(1,387)					(1,387)
Other comprehensive (loss) income, net	38,185				38,185
Ending balance at Dec. 31, 2014	$ 1,000,928	$ 70,500	$ 9	$ 828,327	$ 16,639	$ 85,453
Ending balance, shares at Dec. 31, 2014		71,000	88,691,000