Stock Based Compensation - Stock Compensation Plans (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Stock Options Outstanding
Stock options outstanding, number of shares, balance (in shares) | shares	695,000
Stock options exercised, exercised (in shares) | shares	(1,000)
Stock options outstanding, number of shares, balance (in shares) | shares	694,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Stock options, weighted average exercise price, balance (in dollars per share) | $ / shares	$ 22.42
Stock options, weighted average exercise price, exercised (in dollars per share) | $ / shares	10.65
Stock options, weighted average exercise price, balance (in dollars per share) | $ / shares	$ 22.43
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Stock options outstanding, number of shares, exercisable (in shares) | shares	694,000
Stock options outstanding, weighted average exercise price, exercisable (in dollars per share) | $ / shares	$ 22.43
Non-vested Stock Awards Outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested shares outstanding, balance (in shares) | shares	72,000
Non-vested shares outstanding, vested (earned) (in shares) | shares	(39,000)
Non-vested shares outstanding, forfeited/expired (in shares) | shares	(2,000)
Non-vested shares outstanding, balance (in shares) | shares	31,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share) | $ / shares	$ 21.45
Non-vested shares outstanding. weighted-average grant-date fair value, vested (earned) (in dollars per share) | $ / shares	20.12
Non-vested shares outstanding. weighted-average grant-date fair value, forfeited/expired (in dollars per share) | $ / shares	21.82
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share) | $ / shares	$ 23.16
Non-vested Stock Units Outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested shares outstanding, balance (in shares) | shares	817,000
Non-vested shares outstanding, granted (in shares) | shares	516,000
Non-vested shares outstanding, vested (earned) (in shares) | shares	(334,000)
Non-vested shares outstanding, forfeited/expired (in shares) | shares	(90,000)
Non-vested shares outstanding, balance (in shares) | shares	909,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share) | $ / shares	$ 27.65
Non-vested shares outstanding. weighted-average grant-date fair value, granted (in dollars per share) | $ / shares	26.07
Non-vested shares outstanding. weighted-average grant-date fair value, vested (earned) (in dollars per share) | $ / shares	26.45
Non-vested shares outstanding. weighted-average grant-date fair value, forfeited/expired (in dollars per share) | $ / shares	28.29
Non-vested shares outstanding. weighted-average grant-date fair value, balance (in dollars per share) | $ / shares	$ 27.18