Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended																								6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Preferred stock	Jun. 30, 2013 Preferred stock	Jun. 30, 2014 Preference stock	Jun. 30, 2013 Preference stock	Jun. 30, 2014 Common stock	Jun. 30, 2013 Common stock	Jun. 30, 2014 Additional paid-in capital	Jun. 30, 2013 Additional paid-in capital	Jun. 30, 2014 Retained earnings	Jun. 30, 2013 Retained earnings	Jun. 30, 2014 Accumulated other comprehensive loss	Jun. 30, 2013 Accumulated other comprehensive loss	Jun. 30, 2014 Treasury stock	Jun. 30, 2013 Treasury stock	Dec. 31, 2012 Scenario, Previously Reported	Dec. 31, 2012 Scenario, Previously Reported Preferred stock	Dec. 31, 2012 Scenario, Previously Reported Preference stock	Dec. 31, 2012 Scenario, Previously Reported Common stock	Dec. 31, 2012 Scenario, Previously Reported Additional paid-in capital	Dec. 31, 2012 Scenario, Previously Reported Retained earnings	Dec. 31, 2012 Scenario, Previously Reported Accumulated other comprehensive loss	Dec. 31, 2012 Scenario, Previously Reported Treasury stock	Jun. 30, 2013 Restatement Adjustment	Jun. 30, 2013 Restatement Adjustment Preferred stock	Jun. 30, 2013 Restatement Adjustment Preference stock	Jun. 30, 2013 Restatement Adjustment Common stock	Jun. 30, 2013 Restatement Adjustment Additional paid-in capital	Jun. 30, 2013 Restatement Adjustment Retained earnings	Jun. 30, 2013 Restatement Adjustment Accumulated other comprehensive loss	Jun. 30, 2013 Restatement Adjustment Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period			$ 205,176	$ 127,404	$ 4	$ 4	$ 591	$ 648	$ 323,338	$ 323,338	$ 196,977	$ 223,847	$ 4,715,564	$ 4,761,575	$ (574,556)	$ (681,213)	$ (4,456,742)	$ (4,500,795)	$ 110,631	$ 4	$ 648	$ 323,338	$ 223,847	$ 4,744,802	$ (681,213)	$ (4,500,795)
Retained earnings adjustment (see Note 15)																											16,773	0	0	0	0	16,773	0	0
Net income	94,265	(9,233)	138,938	58,273	0	0	0	0	0	0	0	0	138,938	58,273	0	0	0	0
Other comprehensive income	13,982	(12,520)	15,205	(42,310)	0	0	0	0	0	0	0	0	0	0			0	0
Cash dividends
Common			(75,974)	(113,083)	0	0	0	0	0	0	0	0	(75,974)	(113,083)	0	0	0	0
Preference	(11)	(13)	(22)	(23)	0	0	0	0	0	0	0	0	(22)	(23)	0	0	0	0
Issuances of common stock			(2,023)	1,612	0	0	0	0	0	0	(24,212)	(31,532)	0	0	0	0	22,189	33,144
Conversions to common stock			0	0	(3)	0	(28)	(35)	0	0	(656)	(618)	0	0	0	0	687	653
Stock-based compensation expense			7,976	7,241	0	0	0	0	0	0	7,976	7,241	0	0	0	0	0	0
Purchase of subsidiary shares from noncontrolling interest			(7,520)		0		0		0		(7,520)		0		0		0
Balances, end of period	$ 281,756	$ 39,114	$ 281,756	$ 39,114	$ 1	$ 4	$ 563	$ 613	$ 323,338	$ 323,338	$ 172,565	$ 198,938	$ 4,778,506	$ 4,706,742	$ (559,351)	$ (723,523)	$ (4,433,866)	$ (4,466,998)	$ 110,631	$ 4	$ 648	$ 323,338	$ 223,847	$ 4,744,802	$ (681,213)	$ (4,500,795)