Stockholders' Equity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	$ 188,403	$ 110,631
Net income	44,673	67,506
Other comprehensive income	1,223	(30,761)
Cash dividends
Common	(37,975)	(75,334)
Preference	(14)	(13)
Issuances of common stock	(2,898)	(2,546)
Conversions to common stock	0
Stock-based compensation expense	3,886	3,704
Purchase of subsidiary shares from noncontrolling interest	(7,520)
Balances, end of period	189,778	73,187
Common Stock, Dividends, Per Share, Declared	$ 0.1875	$ 0.375
Preferred stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	4	4
Net income	0	0
Other comprehensive income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	0	0
Conversions to common stock	(3)
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	1	4
Preference stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	591	648
Net income	0	0
Other comprehensive income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	0	0
Conversions to common stock	(28)
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	563	648
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	323,338	323,338
Net income	0	0
Other comprehensive income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	0	0
Conversions to common stock	0
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	323,338	323,338
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	196,977	223,847
Net income	0	0
Other comprehensive income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	(22,655)	(24,097)
Conversions to common stock	(650)
Stock-based compensation expense	3,886	3,704
Purchase of subsidiary shares from noncontrolling interest	(7,520)
Balances, end of period	170,038	203,454
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	4,698,791	4,744,802
Net income	44,673	67,506
Other comprehensive income	0	0
Cash dividends
Common	(37,975)	(75,334)
Preference	(14)	(13)
Issuances of common stock	0	0
Conversions to common stock	0
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	4,705,475	4,736,961
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	(574,556)	(681,213)
Net income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	0	0
Conversions to common stock	0
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	(573,333)	(711,974)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances, beginning of period	(4,456,742)	(4,500,795)
Net income	0	0
Other comprehensive income	0	0
Cash dividends
Common	0	0
Preference	0	0
Issuances of common stock	19,757	21,551
Conversions to common stock	681
Stock-based compensation expense	0	0
Purchase of subsidiary shares from noncontrolling interest	0
Balances, end of period	$ (4,436,304)	$ (4,479,244)