Capital Stock and Equity Awards - Summary of RSU Activity (Details) - RSUs - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Shares
Unvested, beginning of period (in shares)	340,368	300,142
Granted (in shares)	179,016	167,295
Vested (in shares)	(142,830)	(109,545)
Forfeited (in shares)	(1,188)	(1,398)
Unvested, end of period (in shares)	375,366	356,494
Weighted- Average Grant Date Fair Value
Unvested, beginning of period (in dollars per share)	$ 41.50	$ 39.22
Granted (in dollars per share)	43.55	42.07
Vested (in dollars per share)	41.16	39.93
Forfeited (in dollars per share)	42.07	40.26
Unvested, end of period (in dollars per share)	$ 42.61	$ 40.33
Vesting period (in years)	3 years
Non-employee directors
Weighted- Average Grant Date Fair Value
Vesting period (in years)	1 year
Minimum
Weighted- Average Grant Date Fair Value
Vesting period (in years)	1 year
Maximum
Weighted- Average Grant Date Fair Value
Vesting period (in years)	3 years