CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Parent	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit).	Deferred Compensation Employee Stock Trust, Net	Employee Stock Trust	Noncontrolling Interest	Total
Balance at Dec. 31, 2012	$ 1,144,496	$ 114,068	$ 835	$ 1,304,448	$ 8,094	$ (282,949)			$ 2,054	$ 1,146,550
Balance (in shares) at Dec. 31, 2012		114,000	83,487,000
Increase (Decrease) in Stockholders' Equity
Net income	125,342					125,342			1,367	126,709
Other comprehensive income (loss)	(42,957)				(42,957)					(42,957)
Issuance of common stock	86,767		$ 62	86,705						86,767
Issuance of common stock (in shares)			6,208,000
Stock-based compensation expense	1,671			1,671						1,671
Common stock issued to board members	149			149						149
Common stock issued to board members (in shares)			10,000
Issuance of common stock related to share-based awards, net			$ 5	(5)
Issuance of common stock related to share-based awards (in shares)			471,000
Dividends on preferred stock	(4,327)			(4,327)						(4,327)
Net cash distributed to noncontrolling interest									(2,640)	(2,640)
Balance at Dec. 31, 2013	1,311,141	$ 114,068	$ 902	1,388,641	(34,863)	(157,607)			781	1,311,922
Balance (in shares) at Dec. 31, 2013		114,000	90,176,000
Increase (Decrease) in Stockholders' Equity
Net income	111,650					111,650			908	112,558
Other comprehensive income (loss)	35,514				35,514					35,514
Issuance of common stock	3,001			3,001						3,001
Stock-based compensation expense	4,653			4,653						4,653
Common stock issued to board members	208			208						208
Common stock issued to board members (in shares)			9,000
Issuance of common stock related to share-based awards, net	(12)			(12)						(12)
Issuance of common stock related to share-based awards (in shares)			(3,000)
Dividends on preferred stock	(5,703)			(5,703)						(5,703)
Net cash distributed to noncontrolling interest									(902)	(902)
Balance at Dec. 31, 2014	1,460,452	$ 114,068	$ 902	1,390,788	651	(45,957)			787	1,461,239
Balance (in shares) at Dec. 31, 2014		114,000	90,182,000
Increase (Decrease) in Stockholders' Equity
Net income	210,973					210,973			1,606	212,579
Other comprehensive income (loss)	1,978				1,978					1,978
Issuance of common stock	200,033		$ 101	199,932						200,033
Issuance of common stock (in shares)			10,113,000
Stock-based compensation expense	8,250			8,250						8,250
Common stock issued to board members	281			281						281
Common stock issued to board members (in shares)			14,000
Issuance of common stock related to share-based awards, net	346			346						346
Issuance of common stock related to share-based awards (in shares)			(22,000)
Dividends on preferred stock	(1,854)					(1,854)				(1,854)
Redemption of preferred stock	(114,068)	$ (114,068)								(114,068)
Redemption of preferred stock (in shares)		(114,000)
Repurchase of common stock	(30,028)		$ (14)	(22,327)		(7,687)				$ (30,028)
Repurchase of common stock (in shares)			(1,391,000)							(1,390,977)
Deferred compensation plan	591						$ 1,034	$ (443)		$ 591
Deferred compensation plan (in shares)								22,000
Net cash distributed to noncontrolling interest									(1,222)	(1,222)
Balance at Dec. 31, 2015	$ 1,736,954		$ 989	$ 1,577,270	$ 2,629	$ 155,475	$ 1,034	$ (443)	$ 1,171	$ 1,738,125
Balance (in shares) at Dec. 31, 2015			98,896,000					22,000