Stockholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	$ 19,163	$ 29,430	$ 66,395	$ 286,096
Net loss	19,856	(3,329)	(11,685)	(211,812)
Other comprehensive income	16,235	21,612	7,828	3,881
Dividends paid	(8,700)	(8,576)	(17,325)	(17,099)
Issuance of common stock	(241)	14	(4,121)	(1,536)
Stock-based compensation expense	7,057	5,429	12,278	6,950
Balances, end of period	$ 53,370	$ 44,580	$ 53,370	$ 44,580
Dividends paid (USD per share)	$ 0.05	$ 0.05	$ 0.10	$ 0.10
Cumulative Effect
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period				$ (21,900)
Common stock
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	$ 323,338	$ 323,338	$ 323,338	323,338
Balances, end of period	323,338	323,338	323,338	323,338
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	15,269	69,553	68,502	98,748
Issuance of common stock	(16,423)	(6,484)	(74,877)	(37,200)
Stock-based compensation expense	7,057	5,429	12,278	6,950
Balances, end of period	5,903	68,498	5,903	68,498
Retained earnings
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	5,161,029	5,200,024	5,201,195	5,438,930
Net loss	19,856	(3,329)	(11,685)	(211,812)
Dividends paid	(8,700)	(8,576)	(17,325)	(17,099)
Balances, end of period	5,172,185	5,188,119	5,172,185	5,188,119
Retained earnings | Cumulative Effect
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period				(21,900)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	(847,538)	(857,874)	(839,131)	(840,143)
Other comprehensive income	16,235	21,612	7,828	3,881
Balances, end of period	(831,303)	(836,262)	(831,303)	(836,262)
Treasury stock
Increase (Decrease) in Stockholders' Equity
Balances, beginning of period	(4,632,935)	(4,705,611)	(4,687,509)	(4,734,777)
Issuance of common stock	16,182	6,498	70,756	35,664
Balances, end of period	$ (4,616,753)	$ (4,699,113)	$ (4,616,753)	$ (4,699,113)